Abstract:
A magneto-resistance effect head records and reproduces recorded magnetic material. The magneto-resistance effect head has a magneto-resistance effect film connected to a pair of leads. Additionally, a magnetic yoke, with a first and second magnetic yoke member, directs a signal magnetic field from a recording medium to the magneto-resistance effect film. The magneto-resistance effect head is constructed such that the first and second magnetic yoke members have surfaces that face the recording medium. The surfaces of the first and second magnetic yoke members have a magnetic gap between them. Additionally, the magneto-resistance effect film is recessed from the medium facing surfaces by a predetermined distance. Moreover, the first and second magnetic yoke members are aligned almost in parallel with the magnetic flux flow from the recording medium to the first magnetic yoke member, the magneto-resistance effect film, and the second magnetic yoke member.

Description:
This application is a continuation of application Ser. No. 08/529,045 filed Sep. 15, 1995, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a magneto-resistance effect head used as a reproducing head of a magnetic recording/reproducing apparatus and a magnetic recording/reproducing head thereof. 
     2. Description of the Related Art 
     In recent years, high density recording systems such as a VCR with a recording density of 500 MB/inch 2  and a HDD with a recording density of 200 MB/inch 2  have been practically used. In addition, increase of the recording density is further being required. As a reproducing head for use with such high density systems, a magneto-resistance effect head (hereinafter referred to as an MR head) using a magneto-resistance effect of which the electric resistance of such as a magnetic thin film, a magnetic multi-layer thin film, or the like varies by an external magnetic field is becoming attractive. 
     FIG. 22 is a perspective view showing a construction of a conventional shield type MR head. In FIG. 22, reference numeral  1  is a substrate composed of Al 2 O 3 .TiC or the like. A lower shield layer  3  is disposed on the substrate  1  through an insulation layer  2 . The shield layer  3  is composed of permalloy or the like. The insulation layer  2  is composed of Al 2 O 3  or the like. A magneto-resistance effect film (hereinafter referred to as an MR film) is disposed on the lower shield layer  3  through an insulation film  4 . The insulation film  4  forms a reproducing magnetic gap. A pair of leads  6  are connected to both edges of the MR film  5 . As a result, a magneto-resistance effect device  7  (hereinafter referred to as an MR device) is formed. An upper shield layer  9  is disposed on the MR device  7  through an insulation film  8 . The insulation film  8  forms a reproducing magnetic gap. A signal magnetic field is detected by the shield type MR head in the following manner. A sense current is supplied to the leads  6  and then the device resistance that varies corresponding to the variation of the direction of the average magnetization of the MR film  5  is measured. 
     When a signal magnetic field of for example a metal type recording medium is detected by the above-described shield type MR head, the MR head tends to short-circuit the metal type medium. Thus, a large amount of current flows in the MR device  7 , thereby destroying the MR head. In addition, when the MR film  5  is machined in the depth direction, the MR film  5  directly comes in contact with an abrasive solution or the like. During the process, the MR film  5  gets corroded. 
     On the other hand, to prevent the above-described shield type MR head from short-circuiting the metal medium, an insulation protecting film is disposed on the medium opposite surface of the MR head and the medium front surface. However, this method is improper for a low flying that is necessary for improving the linear recording density. In addition, when a contact recording method that is becoming attractive as a future high density recording technology is used, since the medium opposite surface wears out and thereby the protecting film is lost. Thus, to solve such a problem, proper countermeasures should be taken. Moreover, when the MR device  7  wears out, the width in the depth direction varies and thereby the head output fluctuates. In this case, the MR film  5  may wear out and thereby it is lost. 
     As a head construction that prevents such a problem of the above-described shield type MR head, a so-called yoke type MR head as shown in FIG. 23 is known. In this yoke type MR head, the magnetic yoke  10  directs a signal magnetic field to the MR device  7  that is disposed in the head. In the yoke type MR head, the MR device  7  is disposed on a soft magnetic substance layer  11  that is a part of the magnetic yoke  10  through an insulation film  12  that is a magnetic gap. Soft magnetic substances  13  and  14  that are a part of the magnetic yoke are connected from the medium opposite surface to the soft magnetic substance layer  11  in the head through the MR film  5 . In the yoke type MR head, the reproduced output decreases depending on the position of the MR device  7  and the connection of the magnetic yoke  10 . In addition, these overlap lengths L 0V  fluctuate due to an alignment error between each of the soft magnetic substances  13  and  14  that is a part of the magnetic yoke and the MR film  5 , and thereby the reproduced output fluctuates. Thus, it is difficult to produce MR heads with equal characteristics at a high yield rate. 
     On the other hand, a structure as shown in FIG. 24 has been disclosed. In this structure, a magnetic core  15  is disposed in the layer direction of the substrate  1 . The MR device  7  is disposed in the magnetic core  15 . The magnetic permeability in the direction of the film thickness of the magnetic core  15  is almost zero. In addition, the MR device  7  is recessed from the medium facing surface for the film thickness of the magnetic core  15 . Thus, the reproduced output decreases. Moreover, since the production process of a magnetic yoke for such a yoke type MR head is complicated, it is difficult to reduce the production cost. 
     As described above, in the conventional shield type MR head, due to a short-circuit with the metal medium, the head is destroyed. In addition, during the production process, the MR film gets corroded. Due to wear-out of the MR device, the depth thereof varies. Thereby, the head output fluctuates and the MR film is lost. On the other hand, the reproduced output of the conventional yoke type MR head is small and fluctuates. In addition, the production process of the MR head is complicated and the production cost cannot be easily reduced. 
     SUMMARY OF THE INVENTION 
     The present invention is made from the above-described point of view. An object of the present invention is to provide a magneto-resistance effect head and a magnetic recording/reproducing head thereof for suppressing the fluctuation of the reproduced output due to the fluctuation of the depth and overlap length of the yoke to the MR film and for obtaining a good reproduced output at a low cost. 
     A first aspect of the present invention is a magneto-resistance effect head, comprising a magnetic yoke comprising a first magnetic yoke member and a second magnetic yoke member, wherein the first and second magnetic yoke members are disposed with a magnetic gap being between the first and second yoke members at a medium facing surface of the magnetic yoke, a magneto-resistance effect film connected to a pair of leads and disposed on a major surface of the magnetic yoke members at a position recessed from the medium facing surface by a predetermined distance, and the major surface being substantially in parallel with a magnetic flow from the recording medium to the first magnetic yoke member, the magneto-resistance film, and the second magnetic yoke member in this order. 
     A second aspect of the present invention is a magnetic recording/reproducing head, comprising a reproducing head constructed of the magneto-resistance effect head of the first aspect of the present invention, and a recording head including a magnetic core and a recording coil disposed through a magnetic gap and is constructed of an induction type magnetic head having a magnetic core and a magnetic gap that are shared with the magnetic yoke and the magnetic gap of the magneto-resistance effect head. 
     According to the magneto-resistance effect head of the present invention, since the magneto-resistance effect film is disposed on a plane of a magnetic yoke composed of a pair of magnetic substance (for example, along the upper surface of the magnetic yoke in the layer direction), a magneto-resistance effect film can be disposed at a position as close as possible to and recessed from the medium facing surface (namely, at a position adjacent to the medium facing surface). Thus, without loosing the advantages of the yoke type magneto-resistance effect head, much magnetic flux can be directed to the magneto-resistance effect film so as to obtain a highly reproduced output. Even if the medium comes in contact with the head and thereby the head wears out, the fluctuation of the output can be reduced as described later. Thus, since the overlap length between each of the magnetic substances that are the magnetic yoke and the magneto-resistance effect film can be satisfactorily large regardless of the recess position of the magneto-resistance effect film from the medium facing surface, the fluctuation of the reproduced output can be reduced. 
     Moreover, since the track-width is defined by the thickness of the yoke, narrow track of 1 μm or less can be easily fabricated by using the film yoke. 
     The recording head and the reproducing head of the magnetic recording/reproducing head of the present invention can share the magnetic gap and at least a part of the magnetic head of the magneto-resistance effect head and the magnetic core of the induction type magnetic head. Thus, the track width and the gap length in the recording operation are the same as those in the reproducing operation. Consequently, since the alignment error between the recording and reproducing operations becomes zero, the recording/reproducing characteristics of for example a high density recording system can be improved. 
     These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of best mode embodiments thereof, as illustrated in the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view showing an outlined construction of a yoke type magneto-resistance effect head according to an embodiment of the present invention; 
     FIG. 2A is a plan view showing the relation of the positions of the yoke type magneto-resistance effect head shown in FIG. 1 and a recording medium; 
     FIG. 2B is a horizontal sectional view shown in FIG. 2A; 
     FIGS. 3A,  3 B,  3 C,  3 D,  3 E, and  3 F are schematic diagrams for explaining a production method of the magneto-resistance effect head according to the present invention; 
     FIG. 4 is a sectional view showing a magnetic shield layer disposed in the yoke type magneto-resistance effect head shown in FIG. 1; 
     FIG. 5 is a perspective view showing a modification example of the yoke type magneto-resistance effect head shown in FIG. 1; 
     FIG. 6 is a perspective view showing another modification example of the yoke type magneto-resistance effect head shown in FIG. 1; 
     FIG. 7 is a perspective view showing an outlined construction of a magneto-resistance effect head according to another embodiment of the present invention; 
     FIG. 8 is a perspective view showing an outlined construction of a magneto-resistance effect head according to a further other embodiment of the present invention; 
     FIG. 9 is a perspective view showing a modification example of the magneto-resistance effect head shown in FIG. 8; 
     FIG. 10 is a perspective view showing a modification example of the magneto-resistance effective head; 
     FIG. 11 is a perspective view showing a modification example of the magneto-resistance effective head; 
     FIG. 12 is a perspective view showing a modification example of the magneto-resistance effective head; 
     FIG. 13 is a perspective view showing an outlined construction of a magnetic recording/reproducing head according to an embodiment of the present invention; 
     FIG. 14 is a perspective view showing a modification example of the outlined construction of the magnetic recording/reproducing head. 
     FIG. 15 is a perspective view showing a modification example of the outlined construction of the magnetic recording/reproducing head. 
     FIG. 16 is a perspective view showing a modification example of the outlined construction of the magnetic recording/reproducing head. 
     FIG. 17 is a perspective view showing a modification example of the outlined construction of the magnetic recording head according to the present invention. 
     FIG. 18 is a perspective view showing a modification example of the outlined construction of the magnetic recording head according to the present invention. 
     FIG. 19 is a perspective view showing an example of a slider having the magnetic head of the present invention. 
     FIG. 20 is a perspective view showing an example of a slider having the magnetic head of the present invention. 
     FIG. 21 is a perspective view showing an example of a construction of which a plurality of magneto-resistance effect heads according to the present invention are used for a multihead; 
     FIG. 22 is a perspective view showing an outlined construction of a conventional shield type magneto-resistance effect head; 
     FIG. 23 is a perspective view showing an outlined construction of a conventional yoke type magneto-resistance effect head; and 
     FIG. 24 is a perspective view showing an outlined construction of another conventional yoke type magneto-resistance effect head. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Next, embodiments of the present invention will be described in detail. 
     FIGS. 1 and 2 show a construction of a magneto-resistance effect head (referred to as an MR head) according to an embodiment of the present invention. FIG. 1 is a perspective view of the magneto-resistance effect head viewed from a medium facing surface. FIG. 2A is a plane view showing the relation of the positions of the magneto-resistance effect head and a recording medium  40 . FIG. 2B is a sectional view shown in FIG.  2 A. 
     In FIGS. 1,  2 A, and  2 B, reference numeral  21  is a substrate composed of Al 2 O 3 .TiC or the like. An insulation layer  22  is disposed on the substrate  21 . The insulation layer  22  is composed of Al 2 O 3  or the like. A pair of magnetic substances  24  that construct a magnetic yoke  23  are disposed on the insulation layer  22  with a magnetic gap  25  being between the pair of magnetic substances  24  in such a manner that the magnetic substances  24  form the same plane. The magnetic gap  25  is composed of Al 2 O 3  or the like. In other words, the magnetic substances  24 , which construct the magnetic yoke  23 , and the magnetic gap  25  are disposed on the same plane of the substrate through the insulation layer  22 . The magnetic substances  24  are composed of a soft magnetic material (for example, NiFe alloy), an amorphous alloy (for example, CoZrNb), or the like. As a necessary condition, the magnetic gap  25 , which is composed of Al 2 O 3  or the like, is disposed at least between the medium opposite surfaces of the magnetic substances  24 . The magnetic gap  25  disposed between the magnetic substances  24  is suitable for a narrow gap construction. 
     A magneto-resistance effect film (referred to as an MR film)  26  is disposed on a plane almost in parallel with a magnetic flux that passes through the magnetic yoke  23  (namely, a magnetic circuit (denoted by an arrow x of FIG. 2A) at a position recessed from the medium facing surface by a predetermined distance. In other words, the MR film  26  is disposed on a plane equivalent to the upper surface of the layer direction of the magnetic substances  24  so that the MR film  26  is magnetically connected to the magnetic substances  24  through the magnetic gap  25 . The longitudinal direction of the MR film  26  is almost in parallel with the direction of a signal magnetic field directed by the magnetic circuit of the magnetic yoke  23 . 
     The MR film  26  is preferably disposed adjacent to the medium facing surface in consideration of the short-circuit with the recording medium  40 , wear-out, and the like. According to the relation of the positions of the magnetic yoke  23  and the MR film  26 , the MR film  26  can be accurately disposed at a position adjacent to the medium facing surface with a minimum recess therefrom (namely, the advantages of the yoke type MR head are not lost). The recess distance d of the MR film  26  from the medium facing surface is preferably in the range from 0.2 to 10 μm although it depends on the directing amount of the designated signal magnetic field. 
     Examples of the MR film  26  are an anisotropy magneto-resistance effect film, a spin valve film, and an artificial lattice film. The anisotropy magneto-resistance effect film is composed of Ni 80 Fe 20  or the like of which the electric resistance thereof varies corresponding to the angle of the direction of current and the magnetizing moment of the magnetic layer. The spin valve film has a layer structure of a magnetic film and a non-magnetic film of Co 90 Fe 10 /Cu/Co 90 Fe 10  that represents a so-called spin valve effect of which the electric resistance thereof varies corresponding to the angle of each magnetic layer to the magnetization. The artificial lattice film represents a giant magneto-resistance effect. 
     A pair of leads  27  are disposed on the MR film  26 . The leads  27  are composed of Cu or the like and electrically connected to the MR film  26 . As a result, an MR device  28  is constructed. The leads  27  are disposed so that a sense current flows in the longitudinal direction of the MR film  26  that is nearly in parallel with the magnetic circuit produced by the magnetic yoke. As shown in FIG. 2B (not shown in FIG.  1 ), an insulation film  29  is disposed between each of the magnetic substances  24  and the MR film  26 . The MR device  28  is insulated from the magnetic yoke  23 . This construction applies to other embodiments of the present invention. 
     The above-described magneto-resistance effect head is produced in for example the following steps. 
     First, a soft magnetic material film composed of NiFe or CoZrNb is formed on a substrate  21  composed of AlOx/AlOx.TiC or the like. Thereafter, an ion beam is radiated to the resultant structure with a resist mask. As a result, a yoke member  24   a  is formed (see FIG.  3 A). Thereafter, a non-magnetic film  25  composed of AlOx or SiOx and a soft magnetic material film  24  are successively formed on the resultant structure (see FIG.  3 B). A resist  45  with a small molecular weight is coated on the resultant structure and then baked so that the surface of the resultant structure becomes smooth (see FIG.  3 C). Thereafter, for example an ion incident angle is designated so that the resist  5  and the yoke material  24  are etched out at the same etching rate. An ion beam is radiated to the resultant structure so as to form a yoke member  24   b  (see FIG.  3 D). An insulation film  29  composed of AlOx or the like is formed on the front surface of the resultant structure. An MR film or a spin valve film  26  is formed on the front surface of the resultant structure (see FIG.  3 E). Lastly, leads  27  composed of Ti/Cu/Ti or the like are formed by lift-off process or the like (see FIG.  3 F). 
     As shown in FIG. 4, the MR device  28  is preferably covered by a magnetic shield layer  31  through an insulation film  30 . Thus, the MR device  28  can be prevented from being affected by noise due to outer disturbance magnetic field. In addition, when the magnetic shield layer  31  is recessed from the medium opposite surface for around 0.5 μm, the magnetic shield layer  31  prevents the MR film  26  from being affected by a signal magnetic field of an adjacent track. Thus, the MR device  28  can be further prevented from being affected by noise. 
     In the above-described MR head, since the MR film  26  can be accurately disposed at the position recessed from the medium facing surface by the predetermined distance (namely, at the position adjacent to the medium opposite surface), much signal magnetic field can be directed to the MR device  28 . Thus, the output decrease that is one of the disadvantages of the conventional yoke type MR head can be prevented. In addition, the overlap length L OV ′ (see FIG. 1) between each of the magnetic substances  24 , which construct the magnetic yoke  23 , and the MR film  26  can be designated regardless of the distance of the MR film  26  to the medium facing surface, the fluctuation of the reproduced output can be reduced. Next, the effect of the present invention will be quantitatively described. 
     When the medium magnetic flux is sucked by the magnetic substances  24  (thicknesses t 1  and t 2 ; magnetic permeabilities (μ 1  and μ 2 ) that are opposed with the magnetic gap  25  (width: g), the density of the magnetic flux that passes through the magnetic substances attenuates in proportion to the distance from the medium opposite surface. The distance of which the density of magnetic flux that passes through the magnetic substances attenuates to 1/e of the value at the edge of the magnetic substance is denoted by λ and referred to as a characteristic length, where “e” is the base of natural logarithms. The distance λ can be expressed by the following equation. 
     
       
         1λ˜(1 /gμ   1   t   1 +1 /gμ   2   t   2 ) 0.5   
       
     
     For example, in the case that the recording density is 1 GB/inch 2 , for the yoke type MR head shown in FIG. 1, since g=0.25 μm, t 1 =t 2 =2 μm, and μ 1 =μ 2 =1000, the characteristic length λ is around 16 μm. Thus, in the above-described MR head, even if the MR film  26  is recessed from the medium facing surface by around 1.0 μm, most of the magnetic flux that flows in the head can be directed to the MR device  28 . As a result, basically, the output is not decreased. Even if the head wears out for around 0.5 μm, the influence is small. In other words, the magnetic flux that flows in the head slightly increases. Thus, the output fluctuation can be almost ignored. In addition, since the overlap length L OV ′ between each of the magnetic substances  24  and the MR film  26  can be large regardless of the distance of the MR film  26  from the medium facing surface, the fluctuation of the reproduced output is small. 
     In the above-described yoke type MR head, since much magnetic flux flows to the MR device  28 , most portions of the MR device  28  may saturate with a magnetic field. Thus, a resistance fluctuation results in a saturation from the media with large Mr·δ where Mr is remnant magnetisation, δ is the thickness of the media. In this case, as shown in FIG. 5, a center portion of the MR film  26  is bent so as to widen the gap between the MR film  26  and the magnetic yoke  23  so as to adjust the amount of the magnetic flux that flows in the MR film, resulting in suppressing the saturation due to the resistance variation. 
     Moreover, as shown in FIG. 6, when the gap between the magnetic substances  24  (which is a substantial magnetic gap) is a narrow gap g and the width D at which the MR film  26  is disposed wide, the distance between the leads of the MR device  28  can be made as large as D, then the resistance get large to get high output. In addition, when the distance D between the magnetic substances is as large as 0.5 to 1.0 μm with a narrow gap g (for example 0.05-0.2 μm), the portion that is not saturated by the medium magnetic field becomes large. Thus, the saturation due to the resistance variation can be suppressed. Consequently, an MR head with a good linear characteristic can be accomplished. 
     Next, as an example of the yoke type MR head shown in FIG. 6, quantitatively evaluated results of the amount of magnetic flux that flows in the yoke type MR head according to the present invention will be described. In the yoke type MR head shown in FIG. 6, when the gap distance g between medium facing surfaces is denoted 0.1 μm, the depth d thereof is 5 μm (wherein do is approximately 5 μm), the thickness of the MR film  26  is 0.02 μm, and the distance D of the magnetic substances  24  at the position of the MR device  28  is 1 μm, the device magnetic resistance R MR  and the gap magnetic resistance R 1  can be obtained from the following equations. The magnetic permeability of MR is 500. 
     
       
           R   MR ×10 −4 =1/(500×0.02×1)={fraction (1/10)} 
       
     
     
       
           R   1 ×10 −4 =0.1/(1×5×1)={fraction (1/50)} 
       
     
     Thus, the average magnetic flux amount φ MR  which flows in the MR device can be obtained from the following equation assuming that the magnetomotive force between the magnetic substances is 1. 
     
       
         φ MR ×10 4 ∝{1/({fraction (1/50)})}×{({fraction (1/50)})/[({fraction (1/50)})+({fraction (1/10)})]}∝8 
       
     
     
       
         φ MR ∝8×10 −4   
       
     
     where 
     R=1/μs 
     1=length of the magnetic circuit 
     s=area of the cross section 
     μ=magnetic permeability 
     On the other hand, as shown in FIG. 22, in the conventional yoke type MR head, when the overlap length L ov  of the yoke and the MR film is 0.1 μm and the depth d of the magnetic gap portion is 5 μm, r OV  is 1×10 −4  and R g ×10 −4  is {fraction (1/50)}. Thus, the average magnetic flux amount φ YMR  that flows in the MR device is 0.5×10 −4 . When the overlap length L OV  of the yoke to the MR film is as large as 0.2 μm, assuming that the magnetomotive force is 1, the average magnetic flux amount φ YMR  is approximately 1×10 −4 . Thus, it is clear that a small alignment error results in a large fluctuation of the reproduced output. 
     As described above, according to the yoke type MR head of the present invention, more magnetic flux can be directed to the MR device than the conventional yoke type MR head and the conventional shield type MR head. This result is not limited to the yoke type MR head shown in FIG.  6 . Instead, the same effect can be obtained with the another yoke type MR head of the present invention. For example, in the yoke type MR head shown in FIG. 1, when the gap distance g between the medium facing surfaces is 0.1 μm, the distance d of the MR device  28  to the medium facing surface is 5 μm, and the width w of the MR device  28  is 1 μm, assuming that the magnetomotive force between the magnetic substances is 1, the average magnetic flux amount φ MR  that flows in the MR device  28  can be expressed by the following equation. 
     
       
         φ MR ×10 4 ∝{1/({fraction (1/60)})}×{({fraction (1/60)})/[({fraction (1/60)})+({fraction (1/10)})]}∝8 
       
     
     
       
         φ MR ∝8×10 −4   
       
     
     In the above-described embodiment, the construction of which the MR device  28  is disposed on the magnetic yoke  23  (namely, the magnetic substances) was described. However, the present invention is not limited to such a construction. Instead, the same effect can be obtained in the case that the magnetic yoke  23  is disposed on the MR device  28 . For example, as shown in FIG. 7, in the construction of which the MR device  28  (the MR film  26  and the leads  27 ) is disposed on the insulation layer  22  of the substrate  21  at a position recessed from the medium facing surface by a predetermined distance and the magnetic yoke  23  constructed of magnetic substances  24  partially bent in the film thickness direction and the magnetic gap  25  is disposed on the MR device  28 , the same effect as each of the above-described embodiments can be accomplished. In this construction, since the MR device  28  can be disposed on a smooth surface of a substrate, the MR device  28  can suppress an occurrence of magnetic domain walls. In addition, a film at the stair portion can be prevented from being broken. 
     However, when an isotropic magnetic film is used for a yoke film, the magnetic permeability decreases to 500 or less in high frequency range. In contrast, when anisotropic magnetic field is as large as 10 Oe, the magnetic permeability decreases to 500 or less in all frequency range. 
     When a material with a low specific resistance such as NiFe is used, the magnetic permeability in the high frequency range becomes around 300 due to an eddy current loss. In an extreme case, the magnetic permeability becomes 100 or less. In this case, even if the basic construction of the present invention is used, the value of λ is on the order of several λm. 
     Thus, in this case, it is preferable to decrease the recess distance d of the (G) MR device shown in FIG.  1 . In reality, to direct the magnetic flux to the entire region of the (G) MR, it is preferable to decrease the value of (d+w). When (d+w)&lt;λ, the magnetic flux can be necessarily and satisfactorily directed to the (G) MR. 
     Next, with reference to FIGS. 8 and 9, another embodiment of the present invention will be described. 
     In the yoke type MR head shown in FIG. 8, a three-layer structure MR film  34  composed of a pair of magnetic films  32  and a non-magnetic film  33  interposed between the pair of magnetic film. In addition, the MR film  34  is disposed in such a manner that the sense current direction of the MR film  34  becomes almost in parallel with the direction of the magnetic flux produced by the magnetic circuit. 
     As the width w of the MR film  34  is small, the amount of magnetic flux (signal magnetic field) per unit width directed to the MR device  28  can be increased. Thus, the reproduced output is improved. In addition, the MR device  28  is preferably magnetized from the parallel direction of the width of the MR film  34  to the longitudinal direction (the direction of the magnetic flux produced by the magnetic circuit). However, when the MR device is constructed of a single magnetic layer, the magnetization curls in the edge in the width direction. Thus, when the width of the MR film is decreased, the MR device is not magnetized in parallel with the width direction. 
     On the other hand, in the case that the three-layer structure MR film  34  shown in FIG. 8 is used, when the MR device  28  is disposed in such a manner that the direction of the sense current becomes almost in parallel with the direction of the magnetic flux, even if the width w of the MR film  34  is as small as around 3 μm, the magnetic film  32  can be magnetized from the parallel direction of the width to the longitudinal direction. Thus, the direction of the magnetization of the MR film  34  can be properly varied. In addition, the width w of the MR film  34  can be decreased. Consequently, the magnetic flux directed to the MR device  28  per unit width can be increased. Consequently, a large reproduced output can be obtained. At this point, a spin valve film is very suitable for this head. 
     In a construction shown in FIG. 9, a magnetization fixing layer  35  is connected to one of the magnetic films  32  of the three-layer structure MR film  34 . In addition, the fixing direction of the magnetization by the magnetization fixing layer  35  becomes in parallel with the direction of the magnetic flux produced by the magnetic circuit. Moreover, when an anisotropic characteristic is provided or a bias is applied, the linear characteristic of the response to the magnetic field of the medium can be improved. Furthermore, since the magnetic permeability becomes large, the high frequency output can be increased. 
     In MR head, a magnetic moment of a magneto-resistive layer is bias at 45 degree against the vector of a magnetic flux to get linear output. But in this invention, the flux enter the magneto-resistive layer at various angles, so lineality of the output is deteriorated. For example, at left region of the MR element in FIG. 10, the magnetic flux is parallel to the magnetic moment of the magneto-resistive layer, then permeability becomes almost zero. The coil  39  in FIG. 10 is made of one turn. Plural turns may also be used. 
     On the other hand, by using a spin valve element, it is possible to set a magnetic moment of a free layer, which responds to a magnetic field, parallel to y-axis in FIG.  11 . In FIG. 11 magnetic moment of pinned layer is set parallel to x-axis. In this configuration, magnetic flux is almost perpendicular to the magnetic moment of the free layer, therefore linearity of the output is almost conserved. Furthermore, inserting a soft magnetic layer with high resistivity exchange-coupled to the free layer under the spin valve element like in FIG. 12 can avoid magnetic saturation of the free layer when magnetic flux is excessively high at the overlap region. This underlayer makes head design easier and make it possible to supply several types of heads for variety of HDD systems by just optimizing the underlayer thickness. This is a great advantage for production. 
     Next, with reference to FIG. 13, a magnetic recording/reproducing head according to an embodiment of the present invention will be described. 
     The magnetic recording/reproducing head has a reproducing head that has the same construction as the yoke type MR head  36  shown in FIG.  1 . For simplicity, in FIG. 13, the similar portions to those in FIG. 1 are denoted by the similar reference numerals and their description will be omitted. On the other hand, a recording head of the magnetic recording/reproducing head is constructed of an induction type magnetic head  38  that shares the magnetic substances  24  of the magnetic yoke  23  of the yoke type MR head  36  as a part of a magnetic core  37  and the magnetic gap  25 . A recording coil  39  is disposed at the magnetic core  37 . 
     In the above-described magnetic recording/reproducing head, since the track width and the gap length of the recording operation are the same as those of the reproducing operation, the alignment error between the recording operation and the reproducing operation becomes zero. Thus, the production cost can be reduced. If the recording head is spaced apart from the reproducing head, a disk loading is performed. In this case, a track error between the recording and reproducing operations takes place at an inner peripheral position of the disk. In addition, an azimuth loss takes place. However, according to the magnetic recording/reproducing head of the present invention, such problems can be solved. Thus, in a high density recording system with a high linear recording density, excellent recording and reproducing characteristics can be accomplished. 
     In the above-descried magnetic recording/reproducing head, when a current is supplied to a recording coil  39  in the reproducing operation, a bias magnetic field can be applied to the yoke type MR head  36 . Thus, by applying the bias magnetic field to the yoke type MR head  36 , the reproducing characteristics can be improved without need to use an extra bias magnetic field applying means. 
     As described above, according to the magneto-resistance effect head of the present invention, the fluctuation of the reproduced output can be suppressed. In addition, a good reproduced output can be obtained. Thus, in for example a low floating head, high reliability and highly reproduced output can be obtained. Moreover, since the fluctuation of the reproduced output and the production cost are reduced, the head can be quantitatively produced. Furthermore, according to the magnetic recording/ reproducing head of the present invention, since the alignment error between the recording and reproducing operations can be reduced to zero, excellent recording/reproducing characteristics can be obtained at a low cost. 
     FIG. 14 to FIG. 18 show other examples of the invention. FIG. 14 is a read-write head which has a magnetic gap in common for reading and writing. FIG. 15 is a read-write head which has a magnetic gap in common for reading and writing and a spin valve element placed over the yoke region where the distance between the yokes is larger than a magnetic gap length, which make the length of the spin valve element long enough to have the resistance larger than 1 to get higher output. FIG. 16 is a read-write head in which a read head is placed next to the write head and isolated from the write head to get the less magnetic interaction between the write head and the read head to minimize the write-after-noise. FIG.  17  and FIG. 18 are write heads having higher efficiency of writing by making the yoke region, where yokes overpass coils, close to magnetic gaps. FIG. 19 shows an example of the slider having the magnetic head of the invention on the right side of the slider with two air bearing surface. The width of the left air bearing surface is larger than that of the right air bearing surface to make the gap region of the head contact to a media. In FIG. 20, a right part of the slider, which have the magnetic head of the invention on the right side, is projected to ensure the head-to-media contact. 
     Since the magneto-resistance effect head according to the present invention has the above-described construction, it can be used as the following multi-head. 
     When a transmission rate of a HDD or the like is as large as several hundred mega bytes per sec, several heads are required. In this case, as shown in FIG. 21, a plurality of the MR magnetic heads of the present invention are disposed in a stair shape. Thus, reproduction tracks can be formed at very small pitches s. Consequently, this effect is very significant in comparison with the conventional magnetic head. 
     Although the present invention has been shown and described with respect to best mode embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions, and additions in the form and detail thereof may be made therein without departing from the spirit and scope of the present invention.