Abstract:
A ferromagnetic tunnel magnetoresistive film is associated with a high output and whose magnetoresistive ratio is less dependent on a bias voltage. In a three-terminal ferromagnetic tunnel magnetoresistive element, a decrease in an output is suppressed by a bias voltage applied to one of the tunnel junctions. By employing half-metallic ferromagnets in the element, the output can be enhanced and the dependency on the applied bias voltage can be reduced.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a ferromagnetic tunnel magnetoresistive element and a magnetic head using the same.  
         [0003]     2. Description of Related Prior Art Conventionally, ferromagnetic tunnel magnetoresistive (TMR) elements have been proposed as one type of magnetoresistive elements. JP-A-10-4227 describes a magnetic head using a TMR element. However, the magnetoresistance of such a conventional TMR element depends greatly on an applied voltage where a TMR ratio becomes lower as a voltage is applied. In order to employ the TMR element in a magnetic head or a magnetic memory, it is necessary to increase the output while decreasing the dependency thereof on the applied voltage. An increase in the output can be achieved by applying a half-metallic ferromagnet whose degree of spin-polarization is higher than that of a magnetic ferromagnet used in the conventional TMR element. An attempt to increase a TMR ratio in a TMR element using a material associated with a high degree of spin-polarization (La 0.7 Sr 0.3 MnO 3 /SrTiO 3 /La 0.7 Sr 0.3 MnO 3 ) is described in  Europhysics Letters,  39(5), pp. 545-549 (1997).  Physical Review Letters  describes that 40% to 50% TMR ratio can be obtained up to an applied voltage of about 1 V in Co/SrTiO 3 /La 0.7 Sr 0.3 MnO 3 .  
       SUMMARY OF THE INVENTION  
       [0004]     There has been no solution to the decrease in the TMR ratio as well as its dependency on an applied bias voltage. Thus, the present invention has an objective of providing a ferromagnetic tunnel magnetoresistive element whose output is higher and whose magnetoresistive ratio is less dependent on an applied bias voltage compared to conventional elements. In addition, the present invention has an objective of providing a magnetoresistive magnetic head and a magnetic memory device using such a ferromagnetic tunnel magnetoresistive element.  
         [0005]     The degree of spin-polarization (P) of electrons is generally understood as a difference between the numbers (densities of states) of electrons in different rotation directions (about their own axes) (where a clockwise spin is referred to as a downward spin and an anticlockwise spin as an upward spin). For example, the degree of spin-polarization P=0.8 indicates that the number of upward spins is nine times higher than that of downward spins.  
         [0006]     A half-metallic ferromagnet is a completely polarized ferromagnet having a gap of densities of states of upward and downward 3d electronic spins of about 1 eV. Fermi energy (E F ) is present across either one of the densities of state. Since electrons in charge of electronic transport exist at around the Fermi energy, only one of the spins will have a transport property. Thus, the degree of spin-polarization (P) in a half-metallic ferromagnet is 1. On the other hand, ferromagnetic metals such as Co (Co-based alloy), Fe (Fe-based alloy) and Ni (Ni-based alloy) have a degree of polarization of about 0.4, with no gap in the 3d band, and with both upward and downward spins present at Fermi energy.  
         [0007]     The magnetoresistance (TMR ratio) of a TMR element may be represented as 2P 1 P 2 /(1−P 1 P 2 ) using the above-mentioned degree of spin-polarization P, where P 1  and P 2  are degrees of spin-polarization of two respective ferromagnetic layers sandwiching an insulating barrier layer of the TMR element. In order to obtain a high TMR ratio, a half-metallic ferromagnet with a high degree of spin-polarization P (Fe 3 O 4 , CrO 2 , etc.) is advantageously used.  
         [0008]     The dependency of the TMR element on an, applied bias voltage is known to depend on profiles of the densities of states at interfaces of the two ferromagnetic layers with the insulating barrier layer, within the barrier height. Accordingly, a desirable bias voltage dependency of a TMR ratio can be obtained by appropriately combining the insulating barrier layer with the ferromagnetic layers of the TMR element.  
         [0009]     Basically, the present invention has a three-terminal structure including upper ferromagnetic layer/insulating barrier layer/intermediate ferromagnetic layer/insulating barrier layer/lower ferromagnetic layer, each ferromagnetic layer having an electrode terminal. Two electric closed-circuits (for example, a closed-circuit between the upper ferromagnetic layer and the lower ferromagnetic layer, and a closed-circuit between the intermediate ferromagnetic layer and the lower ferromagnetic layer) are provided to vary the bias voltage applied to the tunnel element in one of the closed-circuits, thereby decreasing the bias voltage dependency of a magnetoresistive ratio in the other closed-circuit.  
         [0010]     Specifically, the objective of the present invention can be achieved with the following ferromagnetic tunnel magnetoresistive elements.  
         [0011]     (1) A ferromagnetic tunnel magnetoresistive element, comprising: a first ferromagnetic layer; a first insulating barrier layer formed on the first ferromagnetic layer; a second ferromagnetic layer formed on the first insulating barrier layer; a second insulating barrier layer formed on the second ferromagnetic layer; and a third ferromagnetic layer formed on the second insulating barrier layer, wherein the element further comprises a terminal for applying a first bias voltage between the first ferromagnetic layer and the third ferromagnetic layer, and a terminal for applying a second bias voltage between the second ferromagnetic layer and the first or third ferromagnetic layer.  
         [0012]     (2) A ferromagnetic tunnel magnetoresistive element according to (1), further comprising a first antiferromagnetic layer under the first ferromagnetic layer for fixing the magnetization direction of the first ferromagnetic layer, and a second antiferromagnetic layer on the third ferromagnetic layer for fixing the magnetization direction of the third ferromagnetic layer.  
         [0013]     (3) A ferromagnetic tunnel magnetoresistive element according to either one of (1) and (2), wherein the second ferromagnetic layer is formed of a lamination of three ferromagnetic metal layers.  
         [0014]     (4) A ferromagnetic tunnel magnetoresistive element according to (1), wherein each of the first and second ferromagnetic layers is formed of a lamination of two ferromagnetic metal layers.  
         [0015]     (5) A ferromagnetic tunnel magnetoresistive element according to any one of (1) to (4), wherein at least one of the first, second and third ferromagnetic layers makes contact with a non-magnetic metal layer.  
         [0016]     The objective of the present invention can also be achieved with the following magnetic head.  
         [0017]     (6) A magnetic head provided with a magnetoresistive element comprising: a first ferromagnetic layer; a first insulating barrier layer formed on the first ferromagnetic layer; a second ferromagnetic layer formed on the first insulating barrier layer; a second insulating barrier layer formed on the second ferromagnetic layer; and a third ferromagnetic layer formed on the second insulating barrier layer, wherein the element further comprises a terminal for applying a first bias voltage between the first ferromagnetic layer and the third ferromagnetic layer, and a terminal for applying a second bias voltage between the second ferromagnetic layer and the first or third ferromagnetic layer.  
         [0018]     (7) A magnetic head according to (6), wherein the element further comprises a first antiferromagnetic layer under the first ferromagnetic layer for fixing the magnetization direction of the first ferromagnetic layer, and a second antiferromagnetic layer on the third ferromagnetic layer for fixing the magnetization direction of the third ferromagnetic layer.  
         [0019]     (8) A magnetic head according to either one of (6) and (7), wherein the second ferromagnetic layer is formed of a lamination of three ferromagnetic metal layers.  
         [0020]     (9) A magnetic head according to (6), wherein each of the first and second ferromagnetic layers is formed of a lamination of two ferromagnetic metal layers.  
         [0021]     (10) A magnetic head according to any one of (6) to (9), wherein at least one of the first, second and third ferromagnetic layers makes contact with a non-magnetic metal layer.  
         [0022]     Furthermore, the objective of the present invention can be achieved with the following ferromagnetic tunnel magnetoresistive element.  
         [0023]     (11) A ferromagnetic tunnel magnetoresistive element, comprising: a first half-metallic ferromagnetic layer; a first insulating barrier layer formed on the first half-metallic ferromagnetic layer; a ferromagnetic metal layer formed on the first insulating barrier layer; a second insulating barrier layer formed on the ferromagnetic metal layer; and a second half-metallic ferromagnetic layer formed on the second insulating barrier layer, wherein the element further comprises a terminal for applying a first bias voltage between the first half-metallic ferromagnetic layer and the second half-metallic ferromagnetic layer, and a terminal for applying a second bias voltage between the ferromagnetic metal layer and the first or second half-metallic ferromagnetic layer.  
         [0024]     (12) A ferromagnetic tunnel magnetoresistive element according to (11), further comprising a first antiferromagnetic layer under the first half-metallic ferromagnetic layer for fixing the magnetization direction of the first half-metallic ferromagnetic layer, and a second antiferromagnetic layer on the second half-metallic ferromagnetic layer for fixing the magnetization direction of the second half-metallic ferromagnetic layer.  
         [0025]     (13) A ferromagnetic tunnel magnetoresistive element according to either one of (11) and (12), wherein the ferromagnetic metal layer is formed of a lamination of three ferromagnetic metal layers.  
         [0026]     (14) A ferromagnetic tunnel magnetoresistive element, comprising: a first ferromagnetic metal layer; a first insulating barrier layer formed on the first ferromagnetic metal layer; a half-metallic ferromagnetic layer formed on the first insulating barrier layer; a second insulating barrier layer formed on the half-metallic ferromagnetic layer; and a second ferromagnetic metal layer formed on the second insulating barrier layer, wherein the element further comprises a terminal for applying a first bias voltage between the first ferromagnetic metal layer and the second ferromagnetic metal layer, and a terminal for applying a second bias voltage between the half-metallic ferromagnetic layer and the first or second ferromagnetic metal layer.  
         [0027]     (15) A ferromagnetic tunnel magnetoresistive element according to (14), wherein each of the first and second ferromagnetic metal layers has a lamination of two ferromagnetic metal layers.  
         [0028]     (16) A ferromagnetic tunnel magnetoresistive element according to (14), further comprising a first antiferromagnetic layer under the first ferromagnetic metal layer for fixing the magnetization direction of the first ferromagnetic metal layer, and a second antiferromagnetic layer on the second ferromagnetic metal layer for fixing the magnetization direction of the second ferromagnetic metal layer.  
         [0029]     (17) A ferromagnetic tunnel magnetoresistive element according to any one of (11) to (16), wherein the half-metallic ferromagnetic layer is an oxide or a compound comprising Fe, Co or Mn.  
         [0030]     (18) A ferromagnetic tunnel magnetoresistive element, comprising: a first antiferromagnetic layer; a half-metallic ferromagnetic layer formed on the first antiferromagnetic layer; a first insulating barrier layer formed on the first half-metallic ferromagnetic layer; a first ferromagnetic metal layer formed on the first insulating barrier layer; a second insulating barrier layer formed on the first ferromagnetic metal layer; a second ferromagnetic metal layer formed on the second insulating barrier layer; and a second antiferromagnetic layer formed on the second ferromagnetic metal layer, wherein the element further comprises a terminal for applying a first bias voltage between the half-metallic ferromagnetic layer and the second ferromagnetic metal layer, and a terminal for applying a second bias voltage between the first ferromagnetic metal layer and the half-metallic ferromagnetic layer or the second ferromagnetic metal layer.  
         [0031]     (19) A ferromagnetic tunnel magnetoresistive element according to (18), wherein the first ferromagnetic metal layer is formed of a lamination of three ferromagnetic metal layers.  
         [0032]     (20) A ferromagnetic tunnel magnetoresistive element, comprising: a first antiferromagnetic layer; a first ferromagnetic metal layer formed on the first antiferromagnetic layer; a first insulating barrier layer formed on the first ferromagnetic metal layer; a second ferromagnetic metal layer formed on the first insulating barrier layer; a second insulating barrier layer formed on the second ferromagnetic metal layer; a third ferromagnetic metal layer formed on the second insulating barrier layer; and a second antiferromagnetic layer formed on the third ferromagnetic metal layer, wherein the element further comprises a terminal for applying a first bias voltage between the first ferromagnetic metal layer and the third ferromagnetic metal layer, and a terminal for applying a second bias voltage between the second ferromagnetic metal layer and the first or third ferromagnetic metal layer.  
         [0033]     (21) A ferromagnetic tunnel magnetoresistive element according to any one of (11) to (20), wherein each of the first and second insulating barrier layers is made of an oxide or a compound comprising at least one of Al, Mg, Ti, Ta, Hf, Nb, Mo, Cr, Ga and As.  
         [0034]     The objective of the present invention can also be achieved with the following magnetic head.  
         [0035]     (22) A magnetic head provided with a magnetoresistive element comprising: a first half-metallic ferromagnetic layer; a first insulating barrier layer formed on the first half-metallic ferromagnetic layer; a ferromagnetic metal layer formed on the first insulating barrier layer; a second insulating barrier layer formed on the ferromagnetic metal layer; and a second half-metallic ferromagnetic layer formed on the second insulating barrier layer, wherein the element further comprises a terminal for applying a first bias voltage between the first and second half-metallic ferromagnetic layers, and a terminal for applying a second bias voltage between the ferromagnetic metal layer and the first or second half-metallic ferromagnetic layer.  
         [0036]     (23) A magnetic head according to (22), wherein the element further comprises a first antiferromagnetic layer under the first half-metallic ferromagnetic layer for fixing the magnetization direction of the first half-metallic ferromagnetic layer, and a second antiferromagnetic layer on the second half-metallic ferromagnetic layer for fixing the magnetization direction of the second half-metallic ferromagnetic layer.  
         [0037]     (24) A magnetic head according to either one of (22) and (23), wherein the ferromagnetic metal layer is formed of a lamination of three ferromagnetic metal layers.  
         [0038]     (25) A magnetic head provided with a magnetoresistive element comprising: a first ferromagnetic metal layer; a first insulating barrier layer formed on the first ferromagnetic metal layer; a half-metallic ferromagnetic layer formed on the first insulating barrier layer; a second insulating barrier layer formed on the half-metallic ferromagnetic layer; and a second ferromagnetic layer formed on the second insulating barrier layer, wherein the element further comprises a terminal for applying a first bias voltage between the first ferromagnetic metal layer and the second ferromagnetic metal layer, and a terminal for applying a second bias voltage between the half-metallic ferromagnetic layer and the first or second ferromagnetic metal layer.  
         [0039]     (26) A magnetic head according to (25), wherein each of the first and second ferromagnetic metal layers is formed of a lamination of two ferromagnetic metal layers.  
         [0040]     (27) A magnetic head according to (25), wherein the element further comprises a first antiferromagnetic layer under the first ferromagnetic metal layer for fixing the magnetization direction of the first ferromagnetic metal layer, and a second antiferromagnetic layer on the second ferromagnetic metal layer for fixing the magnetization direction of the second ferromagnetic metal layer.  
         [0041]     (28) A magnetic head according to any one of (22) to (27), wherein the half-metallic ferromagnetic layer is an oxide or a compound comprising Fe, Co or Mn.  
         [0042]     (29) A magnetic head provided with a magnetoresistive element comprising: a first antiferromagnetic layer; a half-metallic ferromagnetic layer formed on the first antiferromagnetic layer; a first insulating barrier layer formed on the first half-metallic ferromagnetic layer; a first ferromagnetic metal layer formed on the first insulating barrier layer; a second insulating barrier layer formed on the first ferromagnetic metal layer; a second ferromagnetic metal layer formed on the second insulating barrier layer; and a second antiferromagnetic layer formed on the second ferromagnetic metal layer, wherein the element further comprises a terminal for applying a first bias voltage between the half-metallic ferromagnetic layer and the second ferromagnetic metal layer, and a terminal for applying a second bias voltage between the first ferromagnetic metal layer and the half-metallic ferromagnetic layer or the second ferromagnetic metal layer.  
         [0043]     (30) A magnetic head according to (29), wherein the first ferromagnetic metal layer is formed of a lamination of three ferromagnetic metal layers.  
         [0044]     (31) A magnetic head provided with a magnetoresistive element comprising: a first antiferromagnetic layer; a first ferromagnetic metal layer formed on the first antiferromagnetic layer; a first insulating barrier layer formed on the first ferromagnetic metal layer; a second ferromagnetic metal layer formed on the first insulating barrier layer; a second insulating barrier layer formed on the second ferromagnetic metal layer; a third ferromagnetic metal layer formed on the second insulating barrier layer; and a second antiferromagnetic layer formed on the third ferromagnetic metal layer, wherein the element further comprises a terminal for applying a first bias voltage between the first ferromagnetic metal layer and the third ferromagnetic metal layer, and a terminal for applying a second bias voltage between the second ferromagnetic metal layer and the first or third ferromagnetic metal layer.  
         [0045]     (32) A magnetic head according to any one of (22) to (31), wherein each of the first and second insulating barrier layers is made of an oxide or a compound comprising at least one of Al, Mg, Ti, Ta, Hf, Nb, Mo, Cr, Ga and As.  
         [0046]     In using the ferromagnetic tunnel magnetoresistive element, a current is provided in a thickness direction of the layers.  
         [0047]     Moreover, the ferromagnetic tunnel magnetoresistive element is preferably formed on an alignment film. Examples of the alignment film include an oxide or a compound containing at least one of Ni, Zr, Zn, Al, Mg, Ti, Ta, Hf, Nb, Mo, Cr and Co. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0048]      FIG. 1  is a schematic cross-sectional view showing one example of a three-terminal ferromagnetic tunnel element of the present invention;  
         [0049]      FIGS. 2A and 2B  are graphs where  FIG. 2A  shows a V 1  dependency of a magnetoresistive ratio of the three-terminal ferromagnetic tunnel element shown in  FIG. 1  where V 2 =0, while  FIG. 2B  shows a V 2  dependency of a magnetoresistive ratio of the three-terminal ferromagnetic tunnel element shown in  FIG. 1  where V 1 =V 1 ′;  
         [0050]      FIG. 3  is a schematic cross-sectional view showing another example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0051]      FIG. 4  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0052]      FIG. 5  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0053]      FIG. 6  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0054]      FIG. 7  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0055]      FIG. 8  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0056]      FIG. 9  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0057]      FIG. 10  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0058]      FIG. 11  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0059]      FIG. 12  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0060]      FIG. 13  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0061]      FIG. 14  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0062]      FIG. 15  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0063]      FIG. 16  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0064]      FIG. 17  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0065]      FIG. 18  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0066]      FIGS. 19A and 19B  are graphs where  FIG. 19A  shows a V 1  dependency of a magnetoresistive ratio of the three-terminal ferromagnetic tunnel element shown in  FIG. 18  where V 2 =0, while  FIG. 19B  shows a V 2  dependency of a magnetoresistive ratio of the three-terminal ferromagnetic tunnel element shown in  FIG. 18  where V 1 =V 1 ′;  
         [0067]      FIG. 20  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0068]      FIG. 21  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0069]      FIG. 22  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0070]      FIG. 23  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0071]      FIG. 24  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0072]      FIG. 25  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0073]      FIG. 26  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0074]      FIG. 27  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0075]      FIG. 28  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0076]      FIG. 29  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0077]      FIG. 30  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0078]      FIG. 31  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0079]      FIG. 32  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0080]      FIG. 33  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0081]      FIG. 34  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0082]      FIG. 35  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0083]      FIGS. 36A and 36B  are graphs where  FIG. 36A  shows a V 1  dependency of a magnetoresistive ratio of the three-terminal ferromagnetic tunnel element shown in  FIG. 35  where V 2 =0, while  FIG. 36B  shows a V 2  dependency of a magnetoresistive ratio of the three-terminal ferromagnetic tunnel element shown in  FIG. 35  where V 1 =V 1 ′;  
         [0084]      FIG. 37  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0085]      FIG. 38  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0086]      FIG. 39  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0087]      FIG. 40  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0088]      FIG. 41  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0089]      FIG. 42  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0090]      FIG. 43  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0091]      FIG. 44  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0092]      FIG. 45  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0093]      FIG. 46  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0094]      FIG. 47  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0095]      FIG. 48  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0096]      FIG. 49  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0097]      FIG. 50  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0098]      FIG. 51  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0099]      FIG. 52  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0100]      FIG. 53  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0101]      FIG. 54  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0102]      FIG. 55  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0103]      FIG. 56  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0104]      FIG. 57  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0105]      FIG. 58  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0106]      FIG. 59  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0107]      FIG. 60  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0108]      FIG. 61  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0109]      FIG. 62  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0110]      FIG. 63  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0111]      FIG. 64  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0112]      FIG. 65  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0113]      FIG. 66  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0114]      FIG. 67  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0115]      FIG. 68  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0116]      FIG. 69  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0117]      FIG. 70  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0118]      FIG. 71  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0119]      FIG. 72  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0120]      FIG. 73  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0121]      FIG. 74  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0122]      FIG. 75  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0123]      FIG. 76  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0124]      FIG. 77  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0125]      FIG. 78  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0126]      FIG. 79  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0127]      FIG. 80  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0128]      FIG. 81  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0129]      FIG. 82  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0130]      FIG. 83  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0131]      FIG. 84  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0132]      FIG. 85  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0133]      FIG. 86  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0134]      FIG. 87  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0135]      FIG. 88  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0136]      FIG. 89  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0137]      FIG. 90  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0138]      FIG. 91  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0139]      FIG. 92  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0140]      FIG. 93  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0141]      FIG. 94  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0142]      FIG. 95  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0143]      FIG. 96  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0144]      FIG. 97  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0145]      FIG. 98  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0146]      FIG. 99  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0147]      FIG. 100  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0148]      FIGS. 101A and 101B  are graphs where  FIG. 101A  shows a V 1  dependency of a magnetoresistive ratio of the three-terminal ferromagnetic tunnel element shown in  FIG. 100  where V 2 =0, while  FIG. 101B  shows a V 2  dependency of a magnetoresistive ratio of the three-terminal ferromagnetic tunnel element shown in  FIG. 100  where V 1 =V 1 ′;  
         [0149]      FIG. 102  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0150]      FIG. 103  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0151]      FIG. 104  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0152]      FIG. 105  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0153]      FIG. 106  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0154]      FIG. 107  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0155]      FIG. 108  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0156]      FIG. 109  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0157]      FIG. 110  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0158]      FIG. 111  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0159]      FIG. 112  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0160]      FIG. 113  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0161]      FIG. 114  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0162]      FIG. 115  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0163]      FIG. 116  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0164]      FIG. 117  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0165]      FIG. 118  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0166]      FIG. 119  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0167]      FIG. 120  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0168]      FIG. 121  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0169]      FIG. 122  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0170]      FIG. 123  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0171]      FIG. 124  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0172]      FIG. 125  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0173]      FIG. 126  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0174]      FIG. 127  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0175]      FIG. 128  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0176]      FIG. 129  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0177]      FIG. 130  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0178]      FIG. 131  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0179]      FIG. 132  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0180]      FIG. 133  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0181]      FIG. 134  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0182]      FIG. 135  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0183]      FIG. 136  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0184]      FIG. 137  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0185]      FIG. 138  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0186]      FIG. 139  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0187]      FIG. 140  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0188]      FIG. 141  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0189]      FIG. 142  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0190]      FIG. 143  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0191]      FIG. 144  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0192]      FIG. 145  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0193]      FIG. 146  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0194]      FIG. 147  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0195]      FIG. 148  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0196]      FIG. 149  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0197]      FIG. 150  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0198]      FIG. 151  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0199]      FIG. 152  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0200]      FIG. 153  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0201]      FIG. 154  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0202]      FIG. 155  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0203]      FIG. 156  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0204]      FIG. 157  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0205]      FIG. 158  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0206]      FIG. 159  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0207]      FIG. 160  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0208]      FIG. 161  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0209]      FIG. 162  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0210]      FIG. 163  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0211]      FIG. 164  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0212]      FIG. 165  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0213]      FIG. 166  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0214]      FIG. 167  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0215]      FIG. 168  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0216]      FIG. 169  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0217]      FIG. 170  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0218]      FIG. 171  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0219]      FIG. 172  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0220]      FIG. 173  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0221]      FIG. 174  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0222]      FIG. 175  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0223]      FIG. 176  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0224]      FIG. 177  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0225]      FIG. 178  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0226]      FIG. 179  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0227]      FIG. 180  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0228]      FIG. 181  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0229]      FIG. 182  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0230]      FIG. 183  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0231]      FIG. 184  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0232]      FIG. 185  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0233]      FIG. 186  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0234]      FIG. 187  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0235]      FIG. 188  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0236]      FIG. 189  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0237]      FIG. 190  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0238]      FIG. 191  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0239]      FIG. 192  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0240]      FIG. 193  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0241]      FIG. 194  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0242]      FIG. 195  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0243]      FIG. 196  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0244]      FIG. 197  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0245]      FIG. 198  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0246]      FIG. 199  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0247]      FIG. 200  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0248]      FIG. 201  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0249]      FIG. 202  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0250]      FIG. 203  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0251]      FIG. 204  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0252]      FIG. 205  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0253]      FIG. 206  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0254]      FIG. 207  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0255]      FIG. 208  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0256]      FIG. 209  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0257]      FIG. 210  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0258]      FIG. 211  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0259]      FIG. 212  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0260]      FIG. 213  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0261]      FIG. 214  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0262]      FIG. 215  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0263]      FIG. 216  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0264]      FIG. 217  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0265]      FIG. 218  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0266]      FIG. 219  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0267]      FIG. 220  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0268]      FIG. 221  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0269]      FIG. 222  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0270]      FIG. 223  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0271]      FIG. 224  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0272]      FIG. 225  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0273]      FIG. 226  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0274]      FIG. 227  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0275]      FIG. 228  is a schematic cross-sectional view showing other example of a three-terminal ferromagnetic tunnel element of the invention;  
         [0276]      FIG. 229  is a schematic perspective view showing a read/write head using a three-terminal ferromagnetic tunnel element of the invention; and  
         [0277]      FIG. 230  is a schematic view showing an exemplary structure of a magnetic writing device provided with the read/write head using the three-terminal ferromagnetic tunnel element of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0278]     Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.  
         [0279]     [Embodiment 1] 
         [0280]     FIGS.  1  to  17  are schematic cross-sectional views showing examples of a three-terminal ferromagnetic tunnel element (hereinafter, referred to as a “three-terminal TMR element”) of the invention. The three-terminal TMR elements shown in FIGS.  1  to  17  each have a basic structure of a half-metallic ferromagnetic layer, an insulating barrier layer, a ferromagnetic metal layer, an insulating barrier layer and a half-metallic ferromagnetic layer laminated in this order on a substrate.  
         [0281]      FIG. 1  is a schematic cross-sectional view showing one example of the three-terminal ferromagnetic tunnel element of the invention. This three-terminal TMR element includes an antiferromagnetic layer  32  (30 nm), a half-metallic ferromagnetic layer  12  (30 nm), an insulating barrier layer  22  (2 nm), a ferromagnetic metal layer  41  (10 nm), an insulating barrier layer  21  (2 nm), a half-metallic ferromagnetic layer  11  (30 nm) and an antiferromagnetic layer  31  (30 nm) laminated in this order on a substrate. An electrode terminal is formed in each of the half-metallic ferromagnetic layers  11  and  12  to form an electric closed-circuit between the layers  11  and  12  (a bias voltage applied by this closed-circuit is defined as V 1 ) while an electrode terminal is formed in each of the ferromagnetic metal layer  41  and the half-metallic ferromagnetic layer  12  to form an electric closed-circuit between the layers  41  and  12  (a bias voltage applied by this closed-circuit is defined as V 2 ). This element was produced by sputtering or deposition technique, and photolithography.  
         [0282]     Arrows in the figure represent directions of currents provided to the element, which may be vice versa as long as the relative relationship of the directions remains the same. Specifically, when the direction of a current of the bias voltage V 1  is reversed with respect to the arrow in  FIG. 1 , the direction of the current of the bias voltage V 2  should also be reversed. The V 2  circuit may be formed between the half-metallic ferromagnetic layer  11  and the ferromagnetic metal layer  41 .  
         [0283]     Hereinafter, materials used for the respective layers of the above-described three-terminal TMR element will be described. The half-metallic ferromagnetic layers  11  and  12  are made from half-metallic ferromagnets with a very high degree of spin-polarization including Fe 3 O 4 , CrO 2 , La 0.7 Sr 0.3 MnO 3 , Sr 2 FeMoO 6  and Mn compounds such as MnSb. The insulating barrier layers  21  and  22  are made of SrTiO 3 , but they may also be made of MgO, HfO 2 , TaO, NbO, MoO, TiO 2  or Al 2 O 3 . The ferromagnetic metal layer  41  is made of CoFe alloy, but it may also be made of Co or NiFe. The antiferromagnetic layers  31  and  32  are made of NiO.  
         [0284]      FIG. 2A  shows an applied bias voltage VI dependency of the TMR ratio of the three-terminal TMR element shown in  FIG. 1  under V 2 =0.  FIG. 2B  shows an applied bias voltage V 2  dependency of the TMR ratio of the three-terminal TMR element shown in  FIG. 1  under V 1 =V 1 ′. Here, V 1 ′ is a value of the applied bias voltage V 1  where the highest TMR ratio is obtained in  FIG. 2A . According to the present example, the bias voltage dependency of the magnetoresistive ratio between the half-metallic ferromagnetic layers  11  and  12  is such that the TMR ratio becomes the highest at about ±0.25 V and decreases at a bias voltage higher than that. By setting V 1  to V 1  and by varying the bias voltage V 2  applied between the ferromagnetic metal layer  41  and the half-metallic ferromagnetic layer  12 , the magnetoresistive ratio can be doubled with a negative bias voltage, thereby reducing the bias voltage dependency.  
         [0285]      FIG. 3  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 1  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from ferromagnetic metal layers  411 ,  412  and  413 . This structure eases the magnetization rotation of the ferromagnetic metal layers  411 ,  412  and  413 . In each of the following examples described with respect to  FIGS. 5, 9  to  11 , and  15  to  17 , the ferromagnetic metal layer  41  is made from three layers for the same reason. The ferromagnetic metal layers  411  and  413  are made of a Co-based alloy (CoFe), and the ferromagnetic metal layer  412  is made of a Ni-based alloy (NiFe). The element of the present example had the same TMR characteristics as those shown in  FIGS. 2A and 2B .  
         [0286]      FIG. 4  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 1  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 2A and 2B . In this example, a soft magnetic half-metallic ferromagnetic layer can be applied. In the following examples described with respect to  FIGS. 5 , and  12  to  17 , the antiferromagnetic layers are not provided adjacent to the half-metallic ferromagnetic layers for this reason.  
         [0287]      FIG. 5  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 3  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 2A and 2B .  
         [0288]      FIG. 6  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 1  except that a non-magnetic metal layer  51  is formed between the insulating barrier layer  21  and the ferromagnetic metal layer  41 . The non-magnetic metal layer  51  may be selected from Au, Cu, Cr, Zn, Ga, Nb, Mo, Ru, Pd, Ag, Hf, Ta, W, Pt and Bi. The element had the same TMR characteristics as those shown in  FIGS. 2A and 2B . By arranging the non-magnetic metal layer adjacent to the ferromagnetic metal layer, the density of states of the bulk of the ferromagnetic metal layer will contribute to conductance, by which the bias voltage dependency of the TMR ratio can be improved. In the following examples described with respect to FIGS.  7  to  17 , non-magnetic metal layers are used for the same reason.  
         [0289]      FIG. 7  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 6  except that a non-magnetic metal layer  51  is formed between the insulating barrier layer  22  and the ferromagnetic metal layer  41 . The element had the same TMR characteristics as those shown in  FIGS. 2A and 2B .  
         [0290]      FIG. 8  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 1  except that a non-magnetic metal layer  51  is formed between the insulating barrier layer  21  and the ferromagnetic metal layer  41 , and a non-magnetic metal layer  52  is formed between the insulating barrier layer  22  and the ferromagnetic metal layer  41 . Similar to the non-magnetic metal layer  51 , the non-magnetic metal layer  52  may be selected from Au, Cu, Cr, Zn, Ga, Nb, Mo, Ru, Pd, Ag, Hf, Ta, W, Pt and Bi. The element had the same TMR characteristics as those shown in  FIGS. 2A and 2B .  
         [0291]      FIG. 9  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 6  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from ferromagnetic metal layers  411 ,  412  and  413 . The ferromagnetic metal layers  411  and  413  are made of a Co-based alloy (CoFe), and the ferromagnetic metal layer  412  is made of a Ni-based alloy (NiFe). The element of the present example had the same TMR characteristics as those shown in  FIGS. 2A and 2B .  
         [0292]      FIG. 10  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 7  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from ferromagnetic metal layers  411 ,  412  and  413 . The ferromagnetic metal layers  411  and  413  are made of a Co-based alloy (CoFe), and the ferromagnetic metal layer  412  is made of a Ni-based alloy (NiFe). The element of the present example had the same TMR characteristics as those shown in  FIGS. 2A and 2B .  
         [0293]      FIG. 11  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 8  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from ferromagnetic metal layers  411 ,  412  and  413 . The ferromagnetic metal layers  411  and  413  are made of a Co-based alloy (CoFe), and the ferromagnetic metal layer  412  is made of a Ni-based alloy (NiFe). The element of the present example had the same TMR characteristics as those shown in  FIGS. 2A and 2B .  
         [0294]      FIG. 12  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 6  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 2A and 2B .  
         [0295]      FIG. 13  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 7  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 2A and 2B .  
         [0296]      FIG. 14  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 8  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 2A and 2B .  
         [0297]      FIG. 15  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 9  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 2A and 2B .  
         [0298]      FIG. 16  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 10  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 2A and 2B .  
         [0299]      FIG. 17  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. This three-terminal TMR element has the same structure as that shown in  FIG. 11  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 2A and 2B .  
         [0300]     In the examples shown in FIGS.  3  to  17 , the bias voltage V 2  may be applied between the half-metallic ferromagnetic layer  11  and the ferromagnetic metal layer  41  ( 412 ).  
         [0301]     [Embodiment 2] 
         [0302]     In the examples shown in FIGS.  18  to  34 , each of the three-terminal TMR elements has a basic structure where a ferromagnetic metal layer, an insulating barrier layer, a half-metallic ferromagnetic layer, an insulating barrier layer and a ferromagnetic metal layer are laminated on a substrate in this order.  
         [0303]      FIG. 18  is a schematic cross-sectional view showing other example of the three-terminal ferromagnetic tunnel element of the invention. The three-terminal TMR element of this example includes an antiferromagnetic layer  32  (30 nm), a ferromagnetic metal layer  42  (5 nm), an insulating barrier layer  22  (2 nm), a half-metallic ferromagnetic layer  11  (30 nm), an insulating barrier layer  21  (2 nm), a ferromagnetic metal layer  41  (5 nm), and an antiferromagnetic layer  31  (30 nm) laminated in this order on a substrate. An electrode terminal is formed in each of the ferromagnetic metal layers  41  and  42  to form an electric closed-circuit between the layers  41  and  42  (a bias voltage applied by this closed-circuit is defined as V 1 ) while an electrode terminal is formed in each of the ferromagnetic metal layer  42  and the half-metallic ferromagnetic layer  11  to form an electric closed-circuit between the layers  42  and  11  (a bias voltage applied by this closed-circuit is defined as V 2 ). This element was produced by sputtering or deposition technique, and photolithography.  
         [0304]     Arrows in the figure represent directions of currents provided to the element, which may be vice versa as long as the relative relationship of the directions remains the same. Specifically, when the direction of a current of the bias voltage V 1  is reversed with respect to the arrow in  FIG. 18 , the direction of the current of the bias voltage V 2  should also be reversed. In this example, the bias voltage V 2  may be applied between the half-metallic ferromagnetic layer  11  and the ferromagnetic metal layer  41 .  
         [0305]     Hereinafter, materials used for the respective layers of the above-described three-terminal TMR element will be described. The half-metallic ferromagnetic layer  11  is made from a half-metallic ferromagnet with very high degree of spin-polarization including Fe 3 O 4 , CrO 2 , La 0.7 Sr 0.3 MnO 3 , Sr 2 FeMoO 6  and Mn compounds such as MnSb. The insulating barrier layers  21  and  22  are made of SrTiO 3 , but they may also be made of MgO, HfO 2 , TaO, NbO, MoO, TiO 2  or Al 2 O 3 . The ferromagnetic metal layers  41  and  42  are made of CoFe alloy, but they may also be made of Co or NiFe. The antiferromagnetic layers  31  and  32  are made of PtMn.  
         [0306]      FIG. 19A  shows an applied bias voltage V 1  dependency of the TMR ratio of the three-terminal TMR element shown in  FIG. 18  under V 2 =0.  FIG. 19B  shows an applied bias voltage V 2  dependency of the TMR ratio of the three-terminal TMR element shown in  FIG. 18  under V 1 =V 1 ′. Here, V 1 ′ is a value of the bias voltage V 1  where the highest TMR ratio is obtained in  FIG. 19A . The three-terminal TMR element of this example has the same effect as that described with reference to  FIGS. 2A and 2B  except that the increase in the magnetoresistive ratio and well bias voltage dependency is obtained with a positive bias voltage due to the arrangement of the material as the ferromagnetic layer.  
         [0307]      FIG. 20  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 18  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  21 . The non-magnetic metal layer  51  is selected from Au, Cu, Cr, Zn, Ga, Nb, Mo, Ru, Pd, Ag, Hf, Ta, W, Pt and Bi. The element had the same TMR characteristics as those shown in  FIGS. 19A and 19B . By arranging the non-magnetic metal layer adjacent to the ferromagnetic metal layer, the effects described with reference to  FIG. 6  can be realized. In the following examples described with respect to FIGS.  22  to  34 , non-magnetic metal layers are arranged adjacent to ferromagnetic metal layers for the same reason.  
         [0308]      FIG. 21  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 20  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 19A and 19B .  
         [0309]      FIG. 22  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 18  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  21 , and a non-magnetic metal layer  52  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  22 . Similar to the non-magnetic metal layer  51 , the non-magnetic metal layer  52  may be selected from Au, Cu, Cr, Zn, Ga, Nb, Mo, Ru, Pd, Ag, Hf, Ta, W, Pt and Bi. The element had the same TMR characteristics as those shown in  FIGS. 19A and 19B .  
         [0310]      FIG. 23  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 18  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  42  is replaced with a tri-layered film made from a ferromagnetic metal layer  421 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  422 . This structure eases the magnetization rotation of the half-metallic ferromagnetic layer  11 . In the following examples, the ferromagnetic metal layer  41  is also replaced with the tri-layered film for the same reason. The ferromagnetic metal layers  414 ,  415 ,  421  and  422  are made of a Co-based alloy. The non-magnetic metal layers  53  and  54  are made of either Ru or Cu. The element of the present example had the same TMR characteristics as those shown in  FIGS. 19A and 19B .  
         [0311]      FIG. 24  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 20  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  42  is replaced with a tri-layered film made from a ferromagnetic metal layer  421 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  422 . The ferromagnetic metal layers  414 ,  415 ,  421  and  422  are made of a Co-based alloy. The non-magnetic metal layers  53  and  54  are made of either Ru or Cu. The element of the present example had the same TMR characteristics as those shown in  FIGS. 19A and 19B .  
         [0312]      FIG. 25  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 21  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  42  is replaced with a tri-layered film made from a ferromagnetic metal layer  421 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  422 . The ferromagnetic metal layers  414 ,  415 ,  421  and  422  are made of a Co-based alloy. The non-magnetic metal layers  53  and  54  may be made of either Ru or Cu. The element of the present example had the same TMR characteristics as those shown in  FIGS. 19A and 19B .  
         [0313]      FIG. 26  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 22  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  42  is replaced with a tri-layered film made from a ferromagnetic metal layer  421 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  422 . The ferromagnetic metal layers  414 ,  415 ,  421  and  422  are made of a Co-based alloy. The non-magnetic metal layers  53  and  54  may be made of either Ru or Cu. The element of the present example had the same TMR characteristics as those shown in  FIGS. 19A and 19B .  
         [0314]      FIG. 27  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 18  without the antiferromagnetic layers  31  and  32 . This structure allows the use of a soft magnetic half-metallic ferromagnetic layer. In the following examples, the antiferromagnetic layers are not provided adjacent to the half-metallic ferromagnetic layers for this reason. The element had the same TMR characteristics as those shown in  FIGS. 19A and 19B .  
         [0315]      FIG. 28  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 21  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 19A and 19B .  
         [0316]      FIG. 29  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 20  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 19A and 19B .  
         [0317]      FIG. 30  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 22  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 19A and 19B .  
         [0318]      FIG. 31  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 27  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 , and the ferromagnetic metal layer  42  is replaced with a double-layered film made from ferromagnetic metal layers  421  and  422 . Replacing the ferromagnetic metal layers  41  and  42  with the double-layered structures eases the magnetization rotation, thereby enhancing magnetization sensitivity of the magnetoresistive ratio. The element of the present example had the same TMR characteristics as those shown in  FIGS. 19A and 19B .  
         [0319]      FIG. 32  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 28  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 , and the ferromagnetic metal layer  42  is replaced with a double-layered film made from ferromagnetic metal layers  421  and  422 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 19A and 19B .  
         [0320]      FIG. 33  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 29  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 , and the ferromagnetic metal layer  42  is replaced with a double-layered film made from ferromagnetic metal layers  421  and  422 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 19A and 19B .  
         [0321]      FIG. 34  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The three-terminal TMR element of this example has the same structure as that shown in  FIG. 30  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 , and the ferromagnetic metal layer  42  is replaced with a double-layered film made from ferromagnetic metal layers  421  and  422 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 19A and 19B . In the structures shown in FIGS.  20  to  34 , the bias voltage V 2  may be applied between the half-metallic ferromagnetic layer  11  and the ferromagnetic metal layer  41  ( 411 ,  414 ).  
         [0322]     [Embodiment 3] 
         [0323]     In the examples shown in FIGS.  35  to  99 , each of the three-terminal TMR elements has a basic structure where a ferromagnetic metal layer, an insulating barrier layer, a ferromagnetic metal layer, an insulating barrier layer and a ferromagnetic metal layer are laminated on a substrate in this order.  
         [0324]      FIG. 35  is a schematic cross-sectional view showing other example of the three-terminal ferromagnetic tunnel element of the invention. The three-terminal TMR element of this example includes an antiferromagnetic layer  32  (12 nm), a ferromagnetic metal layer  43  (3 nm), an insulating barrier layer  22  (1 nm), a ferromagnetic metal layer  42  (5 nm), an insulating barrier layer  21  (1 nm), a ferromagnetic metal layer  41  (3 nm), and an antiferromagnetic layer  31  (12 nm) laminated in this order on a substrate. An electrode terminal is formed in each of the ferromagnetic metal layers  41  and  43  to form an electric closed-circuit between the layers  41  and  43  (a bias voltage applied by this closed-circuit is defined as V 1 ) while an electrode terminal is formed in each of the ferromagnetic metal layer  42  and  43  to form an electric closed-circuit between the layers  42  and  43  (a bias voltage applied by this closed-circuit is defined as V 2 ). This element was produced by sputtering or deposition technique, and photolithography. Arrows in the figure represent directions of currents provided to the element, which may be vice versa as long as the relative relationship of the directions remains the same. In this example, the bias voltage V 2  may be applied between the ferromagnetic metal layers  41  and  42 .  
         [0325]     Hereinafter, materials used for the respective layers of the above-described three-terminal TMR element will be described. The insulating barrier layers  21  and  22  are made of SrTiO 3 , but they may also be made of MgO, HfO 2 , TaO, NbO, MoO, TiO 2  or Al 2 O 3 . The ferromagnetic metal layers  41 ,  42  and  43  are made of CoFe alloy, but they may also be made of Co or NiFe. The antiferromagnetic layers  31  and  32  are made of PtMn.  
         [0326]      FIG. 36A  shows an applied bias voltage V 1  dependency of the TMR ratio of the three-terminal TMR element shown in  FIG. 35  under V 2 =0.  FIG. 36B  shows an applied bias voltage V 2  dependency of the TMR ratio of the three-terminal TMR element shown in  FIG. 35  under V 1 =V 1 ′. Here, V 1 ′ is a value of the bias voltage where the highest TMR ratio is obtained in  FIG. 36A . In the present structure, V 1 ′ is almost 0, but an increase in the magnetoresistive ratio can be realized by varying V 2 . With the bias voltage dependency of the present example, a magnetoresistive ratio of 50% can be obtained when the bias voltage V 2  is +0.5 V.  
         [0327]      FIG. 37  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  21 . By arranging the non-magnetic metal layer to be adjacent to the ferromagnetic metal layer, the effects described with reference to  FIG. 6  can be realized. In the following examples, non-magnetic metal layers are arranged adjacent to ferromagnetic metal layers for the same reason. The non-magnetic metal layer  51  may be selected from Au, Cu, Cr, Zn, Ga, Nb, Mo, Ru, Pd, Ag, Hf, Ta, W, Pt and Bi. The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0328]      FIG. 38  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  21 . The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0329]      FIG. 39  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0330]      FIG. 40  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  43  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0331]      FIG. 41  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  21 , and a non-magnetic metal layer  52  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  22 . Similar to the non-magnetic metal layer  51 , the non-magnetic metal layer  52  may be selected from Au, Cu, Cr, Zn, Ga, Nb, Mo, Ru, Pd, Ag, Hf, Ta, W, Pt and Bi. The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0332]      FIG. 42  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  21 , and a non-magnetic layer  52  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  21 . The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0333]      FIG. 43  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  21 , and a non-magnetic layer  52  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0334]      FIG. 44  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  21 , and a non-magnetic layer  52  is formed between the ferromagnetic metal layer  43  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0335]      FIG. 45  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  22 , and a non-magnetic layer  52  is formed between the ferromagnetic metal layer  43  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0336]      FIG. 46  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  21 , and a non-magnetic layer  52  is formed between the ferromagnetic metal layer  43  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0337]      FIG. 47  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  21 , a non-magnetic layer  52  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  21 , and a non-magnetic metal layer  55  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0338]      FIG. 48  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  21 , a non-magnetic layer  52  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  21 , and a non-magnetic metal layer  55  is formed between the ferromagnetic metal layer  43  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0339]      FIG. 49  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  21 , a non-magnetic layer  52  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  22 , and a non-magnetic metal layer  55  is formed between the ferromagnetic metal layer  43  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0340]      FIG. 50  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  21 , a non-magnetic layer  52  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  22 , and a non-magnetic metal layer  55  is formed between the ferromagnetic metal layer  43  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0341]      FIG. 51  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  21 , a non-magnetic layer  52  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  21 , a non-magnetic metal layer  55  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  22 , and a non-magnetic metal layer  56  is formed between the ferromagnetic metal layer  43  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0342]      FIG. 52  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . This structure eases the magnetization rotation of the ferromagnetic metal layers  423 ,  424  and  425 . In the following examples, the ferromagnetic metal layer  42  is also replaced with the tri-layered film for the same reason. The ferromagnetic metal layers  423  and  425  are made of a Co-based alloy while the ferromagnetic metal layer  424  is made of a Ni-based alloy. The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0343]      FIG. 53  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 37  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0344]      FIG. 54  is a schematic cross-sectional view showing another exemplary three-terminal TMR-element of the invention. The element of this example has the same structure as that shown in  FIG. 38  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0345]      FIG. 55  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 39  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0346]      FIG. 56  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 40  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0347]      FIG. 57  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 41  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0348]      FIG. 58  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in.  FIG. 42  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0349]      FIG. 59  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 43  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0350]      FIG. 60  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 44  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0351]      FIG. 61  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 45  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0352]      FIG. 62  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 46  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0353]      FIG. 63  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 47  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0354]      FIG. 64  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 48  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0355]      FIG. 65  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 49  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0356]      FIG. 66  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 50  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0357]      FIG. 67  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 51  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0358]      FIG. 68  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 35  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The ferromagnetic metal layers  414 ,  415 ,  431  and  432  are made of a Co-based alloy. The non-magnetic metal layers  53  and  54  are made of either Ru or Cu. The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0359]      FIG. 69  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 37  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0360]      FIG. 70  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 38  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0361]      FIG. 71  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 39  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0362]      FIG. 72  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 40  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0363]      FIG. 73  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 41  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0364]      FIG. 74  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 42  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0365]      FIG. 75  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 43  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0366]      FIG. 76  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 44  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0367]      FIG. 77  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 45  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0368]      FIG. 78  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 46  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0369]      FIG. 79  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 47  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0370]      FIG. 80  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 48  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0371]      FIG. 81  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 49  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0372]      FIG. 82  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 50  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0373]      FIG. 83  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 51  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 , and the ferromagnetic metal layer  43  is replaced with a tri-layered film made from a ferromagnetic metal layer  431 , a non-magnetic metal layer  54  and a ferromagnetic metal layer  432 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0374]      FIG. 84  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 68  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0375]      FIG. 85  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 69  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0376]      FIG. 86  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 70  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0377]      FIG. 87  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 71  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0378]      FIG. 88  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 72  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0379]      FIG. 89  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 73  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0380]      FIG. 90  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 74  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0381]      FIG. 91  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 75  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0382]      FIG. 92  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 76  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0383]      FIG. 93  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 77  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0384]      FIG. 94  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 78  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0385]      FIG. 95  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 79  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0386]      FIG. 96  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 80  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0387]      FIG. 97  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 81  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0388]      FIG. 98  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 82  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B .  
         [0389]      FIG. 99  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 83  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 36A and 36B . In the examples shown in FIGS.  37  to  99 , the bias voltage V 2  may be applied between the ferromagnetic metal layers  41  ( 414 ) and  42  ( 424 ).  
         [0390]     [Embodiment 4] 
         [0391]     In the examples shown in FIGS.  100  to  228 , each of the three-terminal TMR elements has a basic structure where a half-metallic ferromagnetic layer, an insulating barrier layer, a ferromagnetic metal layer, an insulating barrier layer and a ferromagnetic metal layer are laminated on a substrate in this order.  
         [0392]      FIG. 100  is a schematic cross-sectional view showing other example of the three-terminal ferromagnetic tunnel element of the invention. The three-terminal TMR element of this example includes an antiferromagnetic layer  32  (30 nm), a half-metallic ferromagnetic layer  11  (30 nm), an insulating barrier layer  22  (2 nm), a ferromagnetic metal layer  42  (10 nm), an insulating barrier layer  21  (1 nm), a ferromagnetic metal layer  41  (5 nm), and an antiferromagnetic layer  31  (12 nm) laminated in this order on a substrate. An electrode terminal is formed in each of the half-metallic ferromagnetic layer  11  and the ferromagnetic metal layer  41  to form an electric closed-circuit between the layers  11  and  41  (a bias voltage applied by this closed-circuit is defined as V 1 ) while an electrode terminal is formed in each of the half-metallic ferromagnetic layer  11  and the ferromagnetic metal layer  42  to form an electric closed-circuit between the layers  11  and  42  (a bias voltage applied by this closed-circuit is defined as V 2 ). This element was produced by sputtering or deposition technique, and photolithography. Arrows in the figure represent directions of currents provided to the element, which may be vice versa as long as the relative relationship of the directions remains the same. In this example, the bias voltage V 2  may be applied between the ferromagnetic metal layers  41  and  42 .  
         [0393]     Hereinafter, materials used for the respective layers of the above-described three-terminal TMR element will be described. The insulating barrier layers  21  and  22  are made of SrTiO 3 , but they may also be made of MgO, HfO 2 , TaO, NbO, MoO, TiO 2  or Al 2 O 3 . The ferromagnetic metal layers  41  and  42  are made of CoFe alloy, but they may also be made of Co or NiFe. The half-metallic ferromagnetic layer  11  is made from a half-metallic ferromagnet with a very high degree of spin-polarization including Fe 3 O 4 , CrO 2 , La 0.7 Sr 0.3 MnO 3 , Sr 2 FeMoO 6  and Mn compounds such as MnSb. The antiferromagnetic layer  32  is made of NiO.  
         [0394]      FIG. 101A  shows an applied bias voltage V 1  dependency of the TMR ratio of the three-terminal TMR element shown in  FIG. 100  under V 2 =0.  FIG. 101B  shows an applied bias voltage V 2  dependency of the TMR ratio of the three-terminal TMR element under V 1 =V 1 ′. Here, V 1 ′ is a value of the bias voltage where the highest TMR ratio is obtained in  FIG. 101A . This example also has the same effect as that described with reference to  FIGS. 2A and 2B . Although the increase in the magnetoresistive ratio is significant at about 0 V due to the arrangement of the material as the ferromagnetic layer, there is no problem.  
         [0395]      FIG. 102  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 100  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  21 . By arranging the non-magnetic metal layer to be adjacent to the ferromagnetic metal layer, the effects described with reference to  FIG. 6  can be realized. In the following examples, non-magnetic metal layers are arranged adjacent to ferromagnetic metal layers for the same reason. The non-magnetic metal layer  51  may be selected from Au, Cu, Cr, Zn, Ga, Nb, Mo, Ru, Pd, Ag, Hf, Ta, W, Pt and Bi. The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0396]      FIG. 103  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 100  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  21 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0397]      FIG. 104  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 100  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0398]      FIG. 105  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 100  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  21 , and a non-magnetic metal layer  52  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  21 . The non-magnetic metal layers  51  and  52  may be selected from Au, Cu, Cr, Zn, Ga, Nb, Mo, Ru, Pd, Ag, Hf, Ta, W, Pt and Bi. The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0399]      FIG. 106  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 100  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  21 , and a non-magnetic metal layer  52  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0400]      FIG. 107  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 100  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  21 , and a non-magnetic metal layer  52  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  22 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0401]      FIG. 108  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 100  except that a non-magnetic metal layer  51  is formed between the ferromagnetic metal layer  41  and the insulating barrier layer  21 , a non-magnetic metal layer  52  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  21 , and a non-magnetic metal layer  53  is formed between the ferromagnetic metal layer  42  and the insulating barrier layer  22 . Similar to the non-magnetic metal layer  51 , the non-magnetic metal layer  53  may be any one of Au, Cu, Cr, Zn, Ga, Nb, Mo, Ru, Pd, Ag, Hf, Ta, W, Pt and Bi. The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0402]      FIG. 109  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 100  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . This structure eases the magnetization rotation of the ferromagnetic metal layers  423 ,  424  and  425 . In the following examples, the ferromagnetic metal layer  42  is also replaced with the tri-layered film for the same reason. The ferromagnetic metal layers  423  and  425  are made of a Co-based alloy while the ferromagnetic metal layer  424  is made of a Ni-based alloy. The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0403]      FIG. 110  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 102  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0404]      FIG. 111  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 103  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0405]      FIG. 112  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 104  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0406]      FIG. 113  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 105  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0407]      FIG. 114  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 106  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0408]      FIG. 115  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 107  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0409]      FIG. 116  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 108  except that the ferromagnetic metal layer  42  is replaced with a tri-layered film made from ferromagnetic metal layers  423 ,  424  and  425 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0410]      FIG. 117  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 100  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The ferromagnetic metal layers  414  and  415  are made of a Co-based alloy. The non-magnetic metal layer  53  is made of either Ru or Cu. The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0411]      FIG. 118  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 102  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0412]      FIG. 119  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 103  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0413]      FIG. 120  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 104  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0414]      FIG. 121  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 105  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0415]      FIG. 122  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 106  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0416]      FIG. 123  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 107  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0417]      FIG. 124  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 108  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0418]      FIG. 125  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 109  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0419]      FIG. 126  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 110  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0420]      FIG. 127  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 111  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0421]      FIG. 128  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 112  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0422]      FIG. 129  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 113  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0423]      FIG. 130  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 114  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0424]      FIG. 131  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 115  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0425]      FIG. 132  is a schematic cross-sectional view showing another exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 116  except that the ferromagnetic metal layer  41  is replaced with a tri-layered film made from a ferromagnetic metal layer  414 , a non-magnetic metal layer  53  and a ferromagnetic metal layer  415 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0426]      FIG. 133  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 100  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B . This structure allows an application of a soft magnetic half-metallic ferromagnetic layer. In some of the following examples, the antiferromagnetic layers are not provided for this reason.  
         [0427]      FIG. 134  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 102  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0428]      FIG. 135  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 103  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0429]      FIG. 136  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 104  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0430]      FIG. 137  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 105  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0431]      FIG. 138  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 106  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0432]      FIG. 139  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 107  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0433]      FIG. 140  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 108  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0434]      FIG. 141  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 109  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0435]      FIG. 142  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 110  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0436]      FIG. 143  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 111  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0437]      FIG. 144  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 112  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0438]      FIG. 145  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 113  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0439]      FIG. 146  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 114  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0440]      FIG. 147  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 115  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0441]      FIG. 148  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 116  without the antiferromagnetic layers  31  and  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0442]      FIG. 149  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 133  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The ferromagnetic metal layer  411  is made of a Co-based alloy while the ferromagnetic metal layer  412  is made of a Ni-based alloy. The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0443]      FIG. 150  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 134  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0444]      FIG. 151  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 135  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0445]      FIG. 152  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 136  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0446]      FIG. 153  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 137  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0447]      FIG. 154  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 138  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0448]      FIG. 155  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 139  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0449]      FIG. 156  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 140  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0450]      FIG. 157  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 141  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0451]      FIG. 158  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 142  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0452]      FIG. 159  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 143  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0453]      FIG. 160  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 144  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0454]      FIG. 161  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 145  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0455]      FIG. 162  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 146  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0456]      FIG. 163  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 147  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0457]      FIG. 164  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 148  except that the ferromagnetic metal layer  41  is replaced with a double-layered film made from ferromagnetic metal layers  411  and  412 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0458]      FIG. 165  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 100  without the antiferromagnetic layer  32 . This structure allows an application of a soft magnetic half-metallic ferromagnetic layer. The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0459]      FIG. 166  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 102  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0460]      FIG. 167  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 103  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0461]      FIG. 168  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 104  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0462]      FIG. 169  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 105  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0463]      FIG. 170  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 106  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0464]      FIG. 171  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 107  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0465]      FIG. 172  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 108  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0466]      FIG. 173  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 109  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0467]      FIG. 174  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 110  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0468]      FIG. 175  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 111  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0469]      FIG. 176  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 112  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0470]      FIG. 177  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 113  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0471]      FIG. 178  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 114  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0472]      FIG. 179  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 115  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0473]      FIG. 180  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 116  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0474]      FIG. 181  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 117  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0475]      FIG. 182  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 118  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0476]      FIG. 183  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 119  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0477]      FIG. 184  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 120  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0478]      FIG. 185  is a schematic cross-sectional view showing, other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 121  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0479]      FIG. 186  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 122  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0480]      FIG. 187  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 123  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0481]      FIG. 188  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 124  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0482]      FIG. 189  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 125  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0483]      FIG. 190  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 126  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0484]      FIG. 191  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 127  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0485]      FIG. 192  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 128  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0486]      FIG. 193  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 129  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0487]      FIG. 194  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 130  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0488]      FIG. 195  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 131  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0489]      FIG. 196  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 132  without the antiferromagnetic layer  32 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0490]      FIG. 197  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 100  without the antiferromagnetic layer  31 . Removal of the antiferromagnetic layer  31  eases magnetization rotation of the ferromagnetic metal layer  41 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0491]      FIG. 198  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 102  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0492]      FIG. 199  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 103  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0493]      FIG. 200  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 104  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0494]      FIG. 201  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 105  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0495]      FIG. 202  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 106  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0496]      FIG. 203  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 107  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0497]      FIG. 204  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 108  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0498]      FIG. 205  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 109  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0499]      FIG. 206  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 110  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0500]      FIG. 207  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 111  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0501]      FIG. 208  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 112  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0502]      FIG. 209  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 113  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0503]      FIG. 210  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 114  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0504]      FIG. 211  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 115  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0505]      FIG. 212  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. The element of this example has the same structure as that shown in  FIG. 116  without the antiferromagnetic layer  31 . The element had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0506]      FIG. 213  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 149  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0507]      FIG. 214  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 150  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0508]      FIG. 215  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 151  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0509]      FIG. 216  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 152  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0510]      FIG. 217  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 153  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0511]      FIG. 218  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 154  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0512]      FIG. 219  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 155  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0513]      FIG. 220  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 156  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0514]      FIG. 221  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 157  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0515]      FIG. 222  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 158  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0516]      FIG. 223  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 159  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0517]      FIG. 224  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 160  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0518]      FIG. 225  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 161  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0519]      FIG. 226  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 162  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0520]      FIG. 227  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 163  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B .  
         [0521]      FIG. 228  is a schematic cross-sectional view showing other exemplary three-terminal TMR element of the invention. According to this example, the lamination film shown in  FIG. 164  is formed on the antiferromagnetic layer  31 . The element of the present example had the same TMR characteristics as those shown in  FIGS. 101A and 101B . In the examples shown in FIGS.  102  to  228 , the bias voltage V 2  may be applied between the ferromagnetic metal layers  41  ( 414 ) and  42  ( 424 ).  
         [0522]      FIG. 229  is a schematic perspective view of a magnetic head provided with a magnetic sensor incorporating a three-terminal TMR element  1  of the invention. The magnetic head is provided with the three-terminal TMR element  1 , Au electrodes  61  and a NiFe upper shield/lower core  60  with a thickness of 1 mm on a base  66 . Coils  64  and an upper core  65  are further formed thereon. The three-terminal TMR element  1  serves as a reader while the upper core  65  and the upper shield/lower core  60  serve as a writer. An Al 2 O 3  insulating layers  62  will prevent an electric leak between the upper magnetic layer and the intermediate magnetic layer of the three-terminal TMR element  1  and an electric leak between the lower magnetic layer and the intermediate magnetic layer of the element  1 . A NiFe lower shield/electrode  63  is used to form an electrode terminal that is introduced in the lower magnetic layer of the three-terminal TMR element  1 .  
         [0523]      FIG. 230  is a schematic view showing an exemplary structure of a magnetic read/write device of the invention. A spindle motor  93  rotates a record medium  91  for magnetically recoding information. An actuator  92  guides a head slider  90  on a track of the record medium  91 . Specifically, in a magnetic disk device, a read head and a write head formed on the head slider  90  will move near a predetermined writing position on the record medium  91  to sequentially write and read signals.  
         [0524]     Preferably, the actuator  92  is a rotary actuator. The write signals are written on the medium by the write head via a signal processor  94 , and the signals are obtained based on an output from the read head via the signal processor  94 . For moving the read head on a predetermined recoding track, a highly-sensitive output from the read head is used to detect the position on the track and the actuator is controlled to align the head slider.  
         [0525]     Although only a single head slider  90  and a single recoding medium  91  are shown in  FIG. 230 , they may be used in multiple. The recoding medium  91  may allow writing information on both sides. When information should be written on both disk faces, the head sliders  90  are arranged on both sides of the disk. The magnetic writing device with the above-described three-terminal TMR element has superior characteristics for coping with a high density than a magnetic writing device provided with a conventional magnetic sensor.  
         [0526]     The present invention provides a three-terminal ferromagnetic tunnel element whose magnetoresistance has an improved bias voltage characteristic due to a bias voltage applied to one of the tunnel junctions. Further, by employing half-metallic ferromagnets in the three-terminal ferromagnetic tunnel element, enhancement of the magnetoresistance to twice the level of conventional ferromagnetic tunnels is stably obtained.