Domain wall motion type magnetic recording element

A magnetic domain wall movement type magnetic recording element includes: a first ferromagnetic layer which includes a ferromagnetic body; a non-magnetic layer which faces the first ferromagnetic layer; and a magnetic recording layer which faces a surface of the non-magnetic layer on a side opposite to the first ferromagnetic layer and extends in a first direction. The magnetic recording layer has a concave-convex structure on a second surface opposite to a first surface which faces the non-magnetic layer.

TECHNICAL FIELD

The present invention relates to a magnetic domain wall movement type magnetic recording element. Priority is claimed on Japanese Patent Application No. 2018-002469, filed Jan. 11, 2018, the content of which is incorporated herein by reference.

BACKGROUND ART

As a next-generation non-volatile memory which replaces a flash memory or the like of which miniaturization has come to a limit, attention has been focused on a resistance change type magnetic recording device which stores data using a resistance change type element. Examples of the magnetic recording device include a magnetoresistive random access memory (MRAM), a resistance random access memory (ReRAM), a phase change random access memory (PCRAM), and the like.

As a method of increasing a density (enlarging a capacity) of a memory, there is a method of multi-valuing recording bits per element constituting the memory, in addition to a method of reducing a size of the element itself constituting the memory.

Patent Literature 1 describes a magnetic domain wall movement type magnetic recording element which can record multi-valued data by moving a magnetic domain wall in a magnetic recording layer. Patent Literature 1 describes that multi-valued data recording is stabilized by providing a trap site in a magnetic recording layer.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

The magnetic domain wall movement type magnetic recording element described in Patent Literature 1 has concavity and convexity on a side surface of the magnetic recording layer. The concavity and convexity serve as a trap site of the magnetic domain wall and control a position of the magnetic domain wall. However, in order to form the concavity and convexity on the side surface, it is necessary to perform post-processing after layers are laminated. In the case of the post-processing, damage or the like occurs on a lamination surface on which a ferromagnetic layer is laminated. The magnetic domain wall movement type magnetic recording element reads and writes data using a change in magnetoresistance. The change in magnetoresistance is caused by a change in the magnetization state between the magnetic recording layer and the ferromagnetic layer which sandwich a non-magnetic layer. Damage to the lamination surface causes a decrease in a magnetoresistance change rate (MR ratio). Further, Patent Literature 1 also describes that the trap site is provided on the lamination surface of the magnetic recording layer. Also in this case, the trap site reduces magnetization stability of a ferromagnetic body and causes noise.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a magnetic domain wall movement type magnetic recording element which controls movement of a magnetic domain wall, curbs a decrease in a magnetoresistance change rate (MR ratio), and has little noise.

Solution to Problem

The present invention provides the following means to solve the above problems.

(1) A magnetic domain wall movement type magnetic recording element according to a first aspect includes a first ferromagnetic layer which includes a ferromagnetic body, a non-magnetic layer which faces the first ferromagnetic layer, and a magnetic recording layer which faces a surface of the non-magnetic layer on a side opposite to the first ferromagnetic layer and extends in a first direction, wherein the magnetic recording layer has a concave-convex structure on a second surface opposite to a first surface which faces the non-magnetic layer.

(2) In the magnetic domain wall movement type magnetic recording element according to the above-described aspect, the first surface may have a smaller arithmetic average roughness than an arithmetic average roughness of the second surface.

(3) In the magnetic domain wall movement type magnetic recording element according to the above-described aspect, in the concave-convex structure, an arrangement of convex portions constituting the concave-convex structure may be irregularly spaced in plan view in a lamination direction.

(4) The magnetic domain wall movement type magnetic recording element according to the above-described aspect may further include a base body which faces the second surface of the magnetic recording layer, and an intermediate body which is located between the base body and the magnetic recording layer.

(5) In the magnetic domain wall movement type magnetic recording element according to the above-described aspect, the intermediate body may be a non-magnetic trap-reinforcing member, and the trap-reinforcing member may be layers which are scattered on one surface of the base body or a layer which has concavity and convexity on the second surface side of the magnetic recording layer.

(6) In the magnetic domain wall movement type magnetic recording element according to the above-described aspect, the intermediate body may have a trap-reinforcing member, and an insulating layer which covers the trap-reinforcing member from a position near the base body, and the trap-reinforcing member may be layers which are scattered on one surface of the base body or a layer which has concavity and convexity on the second surface side of the magnetic recording layer.

(7) In the magnetic domain wall movement type magnetic recording element according to the above-described aspect, one end of the trap-reinforcing member may be in contact with the base body, and when a surface energy of a material constituting a surface of the base body is γA, and a surface energy of a material of the trap-reinforcing member is γB, γB<γA, and a surface energy mismatch ΓABdefined by the following Equation (1) may be larger than 0.5.

(8) In the magnetic domain wall movement type magnetic recording element according to the above-described aspect, a plurality of recording parts which includes the first ferromagnetic layer, the nonmagnetic layer and the magnetic recording layer may be provided, the plurality of recording parts may be arranged in a second direction which intersects the first direction, and the trap-reinforcing member may spread in a same plane over the plurality of recording parts.

(9) In the magnetic domain wall movement type magnetic recording element according to the above-described aspect, a plurality of recording parts which includes the first ferromagnetic layer, the nonmagnetic layer and the magnetic recording layer may be provided, and the trap-reinforcing member or a convex portion of the trap-reinforcing member may extend in a second direction which intersects the first direction over the plurality of recording parts.

(10) In the magnetic domain wall movement type magnetic recording element according to the above-described aspect, the concave-convex structure may have periodicity in the first direction.

(11) In the magnetic domain wall movement type magnetic recording element according to the above-described aspect, the concave-convex structure may have a concave portion or a convex portion having a first shape, and a concave portion or a convex portion having a second shape having a larger volume than that of the first shape.

(12) In the magnetic domain wall movement type magnetic recording element according to the above-described aspect, the concave portion or the convex portion having the second shape may be located at a position at which the concave portion or the convex portion having the second shape overlaps an end surface of the first ferromagnetic layer in plan view in the lamination direction.

(13) In the magnetic domain wall movement type magnetic recording element according to the above-described aspect, the concave or convex portion having the second shape may be larger than the concave or convex portion having the first shape in the first direction.

(14) In the magnetic domain wall movement type magnetic recording element according to the above-described aspect, the concave or convex portion having the second shape may be larger than the concave or convex portion having the first shape in the lamination direction.

(15) In the magnetic domain wall movement type magnetic recording element according to the above-described aspect, a second ferromagnetic layer which reflects a magnetization state of the magnetic recording layer may be provided between the magnetic recording layer and the non-magnetic layer.

(16) A magnetic domain wall movement type magnetic recording element according to a second aspect includes a recording part which includes a first ferromagnetic layer which includes a ferromagnetic body, a magnetic recording layer which is laminated on one side of the first ferromagnetic layer, extends in a first direction which intersects a lamination direction, has a magnetic domain wall, and has a concave-convex structure which traps the magnetic domain wall on a side opposite to the first ferromagnetic layer, and a non-magnetic layer sandwiched between the first ferromagnetic layer and the magnetic recording layer, and a control part which has a planarization layer laminated on a side of the magnetic recording layer opposite to the first ferromagnetic layer and planarizes the concave-convex structure of the magnetic recording layer.

Advantageous Effects of Invention

According to the magnetic domain wall movement type magnetic recording element of the above-described aspect, it is possible to control movement of a magnetic domain wall, to curb a decrease in a magnetoresistance change rate (MR ratio) and to have little noise.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. In the drawings used in the following description, in order to make the characteristics of this invention easy to understand, parts which become features may be enlarged for convenience, and dimensional ratios and the like of the respective components may be different from actual ones. The materials, dimensions, and the like exemplified in the following description are merely examples, and the present invention is not limited thereto and can be implemented with appropriate modifications within a range in which effects of the present invention are exhibited.

(Magnetic Domain Wall Movement Type Magnetic Recording Element)

First Embodiment

FIG. 1is a cross-sectional view schematically showing a magnetic domain wall movement type magnetic recording element100according to a first embodiment. The magnetic domain wall movement type magnetic recording element100includes a recording part60and a control part75. The recording part60includes a first ferromagnetic layer10, a magnetic recording layer20, and a non-magnetic layer30. The recording part60is a part for writing and reading data. The control part75has a base body80and an intermediate body (a planarization layer)70. The control part75is a part provided for forming a concave-convex structure which controls movement of a magnetic domain wall21of the recording part60. The control part75indirectly controls the magnetic domain wall21of the recording part60, but the control part75does not actively control the movement of the magnetic domain wall21. The magnetic domain wall movement type magnetic recording element100shown inFIG. 1includes a first electrode41and a second electrode42at positions which sandwich the first ferromagnetic layer10when seen in a lamination direction of the first ferromagnetic layer10.

Hereinafter, a first direction in which the magnetic recording layer20extends is defined as an x direction, a second direction orthogonal to the x direction in a plane in which the magnetic recording layer20extends is defined as a y direction, and a third direction orthogonal to the x direction and the y direction is defined as a z direction. The lamination direction of the magnetic domain wall movement type magnetic recording element100shown inFIG. 1coincides with the z direction. Further, in the specification, the expression “extending in the x direction” means, for example, that a dimension in the x direction is larger than a minimum dimension among dimensions in the x, y, and z directions. The same applies to the case of extending in other directions.

The first ferromagnetic layer10includes a ferromagnetic body. For example, the first ferromagnetic layer10includes a plurality of layers. Examples of a ferromagnetic material constituting the first ferromagnetic layer10include a metal selected from the group consisting of Cr, Mn, Co, Fe and Ni, an alloy containing at least one of these metals, an alloy containing these metals and at least one element of B, C, and N, and the like. Specifically, Co—Fe, Co—Fe—B, Ni—Fe, CoHo2, SmFe12and the like can be used.

The material forming the first ferromagnetic layer10may be a Heusler alloy. The Heusler alloy is a half-metal and has a high spin polarization. The Heusler alloy is an intermetallic compound having a chemical composition of XYZ or X2YZ, X is a Co—, Fe—, Ni—, or Cu-group transition metal element on the periodic table or a noble metal element, Y is a Mn—, V—, Cr— or Ti-group transition metal or an element represented by X, and Z is a typical element of group III to group V. Examples of the Heusler alloy include Co2FeSi, Co2FeGe, Co2FeGa, Co2MnSi, Co2Mn1-aFeaAlbSi1-b, and Co2FeGe1-cGac, and the like.

The first ferromagnetic layer10may be an in-plane magnetization film having an easy magnetization axis in an in-xy plane direction or may be a perpendicular magnetization film having an easy magnetization axis in the z direction. InFIG. 1, the first ferromagnetic layer10is assumed to be an in-plane magnetization film.

When the easy magnetization axis of the first ferromagnetic layer10is set in the z direction (a perpendicular magnetization film), a thickness of the first ferromagnetic layer10is preferably 1.0 nm or more and 2.5 nm or less and more preferably 1.0 nm or more and 2.0 nm or less. When the first ferromagnetic layer10is formed to be thin, the first ferromagnetic layer10has perpendicular magnetic anisotropy (interface perpendicular magnetic anisotropy) due to an influence of an interface between the first ferromagnetic layer10and another layer (the non-magnetic layer30).

The magnetic recording layer20faces the first ferromagnetic layer10. Here, the term “facing” means opposing another layer and includes a case in which another layer is interposed therebetween. The magnetic recording layer20sandwiches the first ferromagnetic layer10and the non-magnetic layer30. The magnetic recording layer20is laminated on one side (the lower side inFIG. 1) of the first ferromagnetic layer10. The magnetic recording layer20extends in a first direction (the x direction inFIG. 1) which intersects a lamination direction L. The magnetic recording layer20has, for example, a rectangular shape which has a major axis in the x direction and a minor axis in the y direction in plan view in the z direction.

The magnetic recording layer20has a first surface20A which faces the non-magnetic layer30, and a second surface20B which is opposite to the first surface20A. The magnetic recording layer20has a concave-convex structure24which traps the magnetic domain wall21on the second surface20B. The first surface20A has a smaller arithmetic average roughness (Ra) or arithmetic surface roughness than the second surface20B and is flat. The arithmetic average roughness (Ra) is a value obtained by extracting a reference length in a direction of an average line from a roughness curve obtained by measuring the first surface20A or the second surface20B and summing and averaging absolute values of deviations from the average line of the extracted portion to the measure curve. The roughness curves of the first surface20A and the second surface20B are measured along the x direction. The average line is an average position of a height in the z direction and extends in the x direction. The arithmetic surface roughness is a parameter obtained by extending the arithmetic average roughness (Ra) in a surface direction and is an average of absolute values of height differences of respective points with respect to an average surface of the surface. A magnetic potential energy at a convex portion24ais lower than that at a concave portion24b. The magnetic domain wall21is easily trapped by the convex portion24a.

The convex portions24aand the concave portions24bare periodically (equally spaced) or irregularly disposed in the x direction when seen in the z direction. When the convex portions24aand the concave portions24bare periodically disposed in the x direction (refer toFIG. 1), the magnetic domain walls21are trapped at predetermined intervals. As a result, the magnetic domain wall movement type magnetic recording element100can easily perform multi-valued data recording.

FIG. 2is a diagram schematically showing an xz cross section of another example of the magnetic domain wall movement type magnetic recording element according to the first embodiment. In a magnetic domain wall movement type magnetic recording element100A shown inFIG. 2, a distance in the x direction between the adjacent convex portions24ais not constant, and widths of the convex portions24ain the x direction are also different from each other. The convex portions24aand the concave portions24bare disposed irregularly in the x direction. When the convex portions24aand the concave portions24bare disposed irregularly in the x direction, the magnetic domain wall21is trapped irregularly, and the movement of the magnetic domain wall21becomes gentle. As a result, the magnetic domain wall movement type magnetic recording element100can easily record data in an analog manner.

Further,FIG. 3is a diagram schematically showing a yz cross section of another example of the magnetic domain wall movement type magnetic recording element according to the first embodiment. In a magnetic domain wall movement type magnetic recording element100B shown inFIG. 3, a distance in the y direction between adjacent convex portions24ais not constant, and widths of the convex portions24ain the y direction are different from each other. The convex portions24aand the concave portions24bare disposed irregularly in the y direction. As shown inFIG. 3, the convex portions24aand the concave portions24bmay be disposed irregularly in the y direction, there being no limitation to the x direction.

Also,FIG. 4is a diagram schematically showing an xz cross section of another example of the magnetic domain wall movement type magnetic recording element according to the first embodiment. In a magnetic domain wall movement type magnetic recording element100C shown inFIG. 4, a height of each of the convex portions24ain the z direction is not constant. As shown inFIG. 4, the height or depth of each of the convex portions24aand the concave portions24bmay be irregular in the z direction, there being no limitation to the x direction.

The magnetic recording layer20can have the magnetic domain wall21inside. The magnetic domain wall21is a boundary between a first magnetic domain22and a second magnetic domain23having magnetizations in directions opposite to each other. When two magnetic domains are formed inside, the magnetic recording layer20has the magnetic domain wall21inside. In the magnetic domain wall movement type magnetic recording element100shown inFIG. 1, the first magnetic domain22has a magnetization oriented in the +x direction, and the second magnetic domain23has a magnetization oriented in the −x direction.

The magnetic domain wall movement type magnetic recording element100records data in a multi-valued or analog manner according to a position of the magnetic domain wall21of the magnetic recording layer20. Data recorded on the magnetic recording layer20is read as a change in resistance values of the first ferromagnetic layer10and the magnetic recording layer20in the lamination direction. When the magnetic domain wall21moves, the ratio between the first magnetic domain22and the second magnetic domain23in the magnetic recording layer20changes. The magnetization of the first ferromagnetic layer10is in the same direction as (parallel to) the magnetization of the first magnetic domain22and is in a direction opposite (anti-parallel) to the magnetization of the second magnetic domain23. When the magnetic domain wall21moves in the x direction and an area of the first magnetic domain22in a portion which overlaps the first ferromagnetic layer10when seen in the z direction increases, the resistance value of the magnetic domain wall movement type magnetic recording element100decreases. Conversely, when the magnetic domain wall21moves in the −x direction and an area of the second magnetic domain23in a portion which overlaps the first ferromagnetic layer10when seen in the z direction increases, the resistance value of the magnetic domain wall movement type magnetic recording element100increases.

The magnetic domain wall21moves by causing a current to flow in a direction in which the magnetic recording layer20extends or by applying an external magnetic field. For example, when a current pulse is applied from the first electrode41to the second electrode42, the first magnetic domain22spreads in a direction of the second magnetic domain23, and the magnetic domain wall21moves in the direction of the second magnetic domain23. That is, the position of the magnetic domain wall21is controlled by setting a direction and intensity of the current flowing through the first electrode41and the second electrode42, and data is written to the magnetic domain wall movement type magnetic recording element100.

The magnetic recording layer20is configured of a magnetic body. The same magnetic body as that of the first ferromagnetic layer10can be used for the magnetic body constituting the magnetic recording layer20. Further, the magnetic recording layer20preferably contains at least one element selected from the group consisting of Co, Ni, Pt, Pd, Gd, Tb, Mn, Ge, and Ga. For example, a laminated film of Co and Ni, a laminated film of Co and Pt, a laminated film of Co and Pd, a MnGa-based material, a GdCo-based material, and a TbCo-based material can be used. Ferrimagnetic bodies such as MnGa-based materials, GdCo-based materials, and TbCo-based materials have a small saturation magnetization and can reduce a threshold current required for moving a magnetic domain wall. Furthermore, the laminated film of Co and Ni, the laminated film of Co and Pt, and the laminated film of Co and Pd have a large coercivity and can curb a movement speed of the magnetic domain wall.

The non-magnetic layer30is sandwiched between the first ferromagnetic layer10and the magnetic recording layer20. A known material can be used for the non-magnetic layer30. For example, when the non-magnetic layer30is made of an insulator (when it is a tunnel barrier layer), a material thereof may be Al2O3, SiO2, MgO, MgAl2O4, or the like. In addition, materials in which Al, Si, and Mg are partially replaced by Zn, Be, or the like can be used as the non-magnetic layer30. Among them, MgO and MgAl2O4are materials capable of realizing coherent tunneling, and spin can be implanted efficiently. When the non-magnetic layer30is made of a metal, Cu, Au, Ag, or the like can be used as the material thereof. Furthermore, when the non-magnetic layer30is made of a semiconductor, the material thereof may be Si, Ge, CuInSe2, CuGaSe2, Cu(In, Ga)Se2, or the like.

The first electrode41and the second electrode42are disposed at positions which sandwich the first ferromagnetic layer10in the x direction when seen in the z direction. The first electrode41and the second electrode42may be made of a conductive material such as Cu, Al, and Au. Further, the first electrode41may be a ferromagnetic body in which the magnetization is oriented in the x direction, and the second electrode42may be a ferromagnetic body in which the magnetization is oriented in the −x direction. When a current passes through the first electrode41or the second electrode42, the current is spin-polarized. When the spin-polarized current is applied to the magnetic recording layer20, the ratio between the first magnetic domain22and the second magnetic domain23of the magnetic recording layer20changes.

The first electrode41and the second electrode42may be replaced with spin-orbit torque wiring. For example, spin-orbit torque wiring which extends in the y direction is arranged at the positions of the first electrode41and the second electrode42. When a current flows through the spin-orbit torque wiring, a spin Hall effect occurs in the spin-orbit torque wiring. When the spin polarized by the spin Hall effect flows into the magnetic recording layer20, the ratio between the first magnetic domain22and the second magnetic domain23of the magnetic recording layer20changes. Both the first electrode41and the second electrode42may be replaced with the spin-orbit torque wiring, or only one thereof may be replaced. When both are replaced with the spin-orbit torque wiring, the direction of current flowing is reversed.

The first electrode41and the second electrode42may not be provided. In this case, the magnetic domain wall of the magnetic recording layer20is moved by an external magnetic field.

The intermediate body70is located between the base body80and the magnetic recording layer20. The intermediate body70fills the concave-convex structure24on the second surface20B of the magnetic recording layer20and makes it flat. When seen from the magnetic recording layer20, the intermediate body70can be regarded as a planarization layer.

The intermediate body70shown inFIG. 1is a layer having concavity and convexity on a first surface70A on a second surface20B side of the magnetic recording layer20. The first surface70A of the intermediate body70has a concave-convex structure74including a convex portion74aand a concave portion74b. The magnetic recording layer20is laminated on the first surface70A of the intermediate body70. The concave-convex structure24of the magnetic recording layer20B is formed by the concave-convex structure74on the first surface70A of the intermediate body70. The convex portion74aof the intermediate body70corresponds to the concave portion24bof the magnetic recording layer20, and the concave portion74bof the intermediate body70corresponds to the convex portion24aof the magnetic recording layer20.

The intermediate body70shown inFIG. 1is a non-magnetic body. The intermediate body70shown inFIG. 1is an example of a trap-reinforcing member which will be described later. When a surface of the base body80is formed of an insulator, the intermediate body70may be a conductor or an insulator. When the surface of the base body80is a conductor, the intermediate body70is preferably an insulator. When the intermediate body70has an insulating property, a current flowing between the first electrode41and the second electrode42can be prevented from flowing through a portion other than the magnetic recording layer20. When resistance of the intermediate body70is sufficiently higher than that of the magnetic recording layer20, a conductor, a semiconductor, or the like may be used for the intermediate body70.

A thickness of the intermediate body70is preferably 20 nm or less, more preferably 10 nm or less, and even more preferably 5 nm or less. The thickness of the intermediate body70is preferably 2 nm or more. Here, the thickness of the intermediate body70is a distance between an average height position of the first surface70A and the second surface70B of the intermediate body70. The average height position is a position obtained by averaging the height positions of concavity and convexity on the first surface70A and can be confirmed by a transmission electron microscope. When the thickness of the intermediate body70is within the above-described range, the concave-convex structure74having a sufficient concave-convex difference on the first surface70A of the intermediate body70can be formed.

FIG. 5is a plan view schematically showing the magnetic domain wall movement type magnetic recording element100according to the first embodiment. InFIG. 5, the convex portions74aof the intermediate body70are irregularly disposed in a xy plane. Here, the term “irregular” in this specification means that a distance between vertices of the adjacent convex portions74ais not constant. The fact that the distance between the vertices of the adjacent convex portions74ais not constant is obtained as follows. First, the distances L1, L2, L3, . . . between the vertices of the convex portions74alocated at positions which overlaps the magnetic recording layer20are determined. Then, a most frequent value of the distances between the vertices of the convex portions74ais obtained. When each of the distances L1, L2, L3, . . . between the vertices of the convex portions74ais within a range of ±5% of the most frequent value, the distances between the vertices of the adjacent convex portion74aare considered to be constant. Conversely, when the condition is not satisfied, it can be determined that the distances between the vertices of the adjacent convex portions74aare not constant and the convex portions74aare irregularly disposed in the xy plane. The magnetic recording layer20, the non-magnetic layer30, and the first ferromagnetic layer10are sequentially laminated on the intermediate body70. The convex portion24aand the concave portion24bof the magnetic recording layer20are formed irregularly.FIG. 5shows an example in which the convex portions74aof the intermediate body70are irregular, but the convex portions74aof the intermediate body70may be disposed regularly.

The base body80has, for example, a substrate and an underlayer laminated on one surface of the substrate on the intermediate body70side. The substrate is, for example, a semiconductor substrate such as silicon. The base body80may have only the substrate without the underlayer.

The underlayer is, for example, Fe, Cu, Ni, Co, Si, SiO2, Al2O3, MgO, or the like. The concavity and convexity on the first surface70A of the intermediate body70are formed in relation to the underlayer. For example, crystal growth of the intermediate body70becomes granular due to the underlayer, and the concavity and convexity are formed on the first surface70A of the intermediate body70. In addition, for example, the concavity and convexity are formed on the first surface70A of the intermediate body70using the difference in surface energy between the underlayer and the intermediate body70.

Next, an example of a method for manufacturing the magnetic domain wall movement type magnetic recording element100according to the first embodiment will be described with reference toFIGS. 6A to 6F.

First, the base body80is prepared. The base80has a substrate81and an underlayer82. Then, as shown inFIG. 6A, the intermediate body70is formed on one surface of the underlayer82. The intermediate body70is laminated by, for example, a sputtering method, a chemical vapor deposition (CVD) method, or the like. The first surface70A of the intermediate body70has concavity and convexity in relation to the underlayer82. For example, when a crystal of the intermediate body70and a crystal of the underlayer82have different lattice constants, a crystal structure is disturbed to reduce the difference in the lattice constant, and the concavity and convexity are formed on the first surface70A. Also, for example, when there is a difference in surface energy between the underlayer82and the intermediate body70, the concavity and convexity are formed on the first surface70A. For example, atoms constituting the intermediate body70sputtered on one surface of the underlayer82aggregate with each other due to the difference in the surface energy. The atoms which are aggregated together are scattered in an island shape. When film formation of the intermediate body70is continued, the islands are combined with each other, and the intermediate body70having the concavity and convexity on the first surface70A is formed. The positions in the x direction and the positions in the y direction of the convex portions of the concavity and convexity formed on the first surface70A may be regular or irregular, and the heights of the convex portions in the z direction may be constant or different.

Next, as shown inFIG. 6B, a magnetic body28is laminated on one surface of the intermediate body70. A first surface28A of the magnetic body28has concavity and convexity which reflect a shape of the first surface70A of the intermediate body70.

Further, as shown inFIG. 6C, anisotropic sputtering may be performed when the magnetic body28is laminated. The anisotropic sputtering is a method in which ions are sputtered to a film-forming object (the intermediate body70) in an oblique direction. When ions are supplied in an oblique direction, a film forming speed changes in a plane of the film-forming body (the intermediate body70), and the first surface28A of the magnetic body28is planarized with respect to the first surface70A of the intermediate body70.

Next, as shown inFIG. 6D, the first surface28A of the magnetic body28is planarized. The planarization is performed by, for example, chemical mechanical polishing, dry etching, wet etching, or the like. As shown inFIG. 6C, when the anisotropic sputtering is performed, a process in which the first surface28A is planarized may not be performed.

Next, as shown inFIG. 6E, a magnetic body29is laminated on the first surface28A of the magnetic body28. The magnetic body28and the magnetic body29are the same. The magnetic body28and the magnetic body29are combined to form the magnetic recording layer20.

Next, as shown inFIG. 6F, the non-magnetic layer30and the first ferromagnetic layer10are sequentially laminated on one surface of the magnetic recording layer20. Then, unnecessary portions of the non-magnetic layer30and the first ferromagnetic layer10are removed by photolithography or the like. With such a procedure, the magnetic domain wall movement type magnetic recording element100according to the first embodiment can be manufactured.

As described above, since the magnetic domain wall movement type magnetic recording element100according to the first embodiment has the concave-convex structure24on a surface of the magnetic recording layer20on the back surface side (the side opposite to the first ferromagnetic layer10), and the concave-convex structure24serves as a trap site for the magnetic domain wall21, controllability of the movement of the magnetic domain wall21can be improved. Further, the second surface20B on which the concave-convex structure24is formed corresponds to a back surface of the first surface20A on which the first ferromagnetic layer10is laminated, and has little effect on the MR ratio of the magnetic domain wall movement type magnetic recording element100. That is, noise of the magnetic domain wall movement type magnetic recording element100can be curbed.

Further, when a trap site is separately provided around the magnetic recording layer20, it is necessary to maintain a predetermined distance between the magnetic recording layer20and the trap site due to a process restriction. On the other hand, in the embodiment, the back surface of the magnetic recording layer20is the trap site, the magnetic domain wall21can be trapped at a closer position than a case in which the trap site is provided around the magnetic recording layer20, and thus the controllability of the movement of the magnetic domain wall21can be further improved. Further, when the trap site is provided on a side surface of the magnetic recording layer20, the concavity and convexity in which a difference between the concavity and convexity is about a few tens of nm are formed on the side surface due to a problem of processing accuracy of photolithography or the like. In other words, an extra space of about a few tens of nm is required outside the first ferromagnetic layer10. On the other hand, the magnetic domain wall movement type magnetic recording element100according to the embodiment has the trap site in the z direction and does not require an extra space in the xy directions.

Further, since the magnetic domain wall movement type magnetic recording element100according to the embodiment does not have the concave-convex structure24on the surface side (the first ferromagnetic layer10side), a problem that noise is generated when a density of a current flowing on the surface side becomes discontinuous in the concave-convex structure can be avoided.

Further, the magnetic domain wall movement type magnetic recording element100according to the embodiment does not require physical processing of the first ferromagnetic layer in the manufacturing process and can also avoid a problem that noise is generated at the time of operation due to an effect of processing damage.

Although an example of the first embodiment has been described in detail, the first embodiment is not limited to this example, and various modifications and changes may be made within the scope of the present invention described in the appended claims.

FIG. 7is a cross-sectional view schematically showing Modified Example 1 of the magnetic domain wall movement type magnetic recording element according to the first embodiment. A magnetic domain wall movement type magnetic recording element100D according to Modified Example 1 is different from the magnetic domain wall movement type magnetic recording element100shown inFIG. 1in that the intermediate body70has no layer formed and is scattered on one surface of the base body80. Also in this case, the second surface20B of the magnetic recording layer20has the concave-convex structure24, and the same effect as in the magnetic domain wall movement type magnetic recording element100can be obtained.

The magnetic domain wall movement type magnetic recording element100D according to Modified Example 1 is manufactured by stopping the film formation of the intermediate body70before the islands are combined when the intermediate body70is laminated.

Second Embodiment

FIG. 8is a schematic cross-sectional view of a magnetic domain wall movement type magnetic recording element according to a second embodiment. The magnetic domain wall movement type magnetic recording element101shown inFIG. 8is different from the magnetic domain wall movement type magnetic recording element100shown inFIG. 1in that the intermediate body70includes a trap-reinforcing member90and an insulating layer91which covers the trap-reinforcing member90from a position near the base body80. The same parts as those of the magnetic domain wall movement type magnetic recording element100are designated by the same reference numerals, and description thereof will be omitted.

InFIG. 8, the trap-reinforcing member90is scattered on one surface of the base body80. The trap-reinforcing member90may be made of a non-magnetic material such as Ta, Al, or Cu, or may be made of a magnetic material such as Ni, Fe, or Co. When the trap-reinforcing member90is made of a non-magnetic material, the difference in magnetic potential energy can be clarified between the convex portion24aand the concave portion24bin the concave-convex structure24of the magnetic recording layer, and a magnetic domain wall trapping function can be enhanced. Further, when the trap-reinforcing member90is made of a magnetic material, the magnetic domain wall21can be trapped more strongly by magnetically coupling with the magnetization of the magnetic recording layer20, as compared with the case in which the trap-reinforcing member90is made of a non-magnetic material.

When a film is formed by sputtering a material to form the insulating layer91after \the trap-reinforcing member90is formed, according to film forming conditions, the ratio of the thickness of a planarization material to be formed can be adjusted at an upper surface and a side surface of the trap-reinforcing member90. At this time, the ratio between the width of the trap-reinforcing member90and the thickness of the planarization material is 1:1 to 2:1. Therefore, in an extending direction (the x direction) of the magnetic recording element20, the width of the trap-reinforcing member90is about 0.3 to 0.5 times the width of the concave portion24b.

The insulating layer91covers the surface of the trap-reinforcing member90scattered in an island shape. The insulating layer91is formed by reflecting surface shapes of the base body80and the trap-reinforcing member90. Therefore, the concave-convex structure74including the convex portion74aand the concave portion74bis formed on the first surface70A of the intermediate body70. Since the magnetic recording layer20is formed on the first surface70A of the intermediate body70, the second surface20B has the concave-convex structure24.

In the insulating layer91, at least a portion between an inner wall of the concave portion24band the trap-reinforcing member90has insulating properties. The insulating layer91preferably has insulating properties as a whole. The insulating layer91electrically separates the magnetic recording layer90from the base body80. The base body80is formed on the side of the intermediate body70opposite to the magnetic recording layer20. The base body80is in contact with one end of the trap-reinforcing member90.

When a surface energy of a material constituting the surface of the base body80is γA, and a surface energy of a material of the trap-reinforcing member90is γB, γB<γA, and a surface energy mismatch ΓABdefined by the following Equation (1) is preferably larger than 0.5. Here, the material constituting the surface of the base body80is a material which constitutes the underlayer when the base body80is formed of the substrate and the base layer, and the material is a material which constitutes the substrate when the base body80is formed of the substrate. In the first embodiment, the material constituting the intermediate body70and the material constituting the surface of the base body80also preferably satisfy the same relationship.

When the surface energy of the surface of the base body80and the surface energy of the trap-reinforcing member90satisfy the above relationship, the trap-reinforcing member90grows in an island shape only by performing a film forming process. In this case, since patterning for forming the trap-reinforcing member90is not required, the manufacturing process can be simplified.

Table 1 shows an example of a combination of materials of the surface of the base body80and the trap-reinforcing member90which satisfies the above relationship.

Next, an example of a method for manufacturing the magnetic domain wall movement type magnetic recording element101according to the second embodiment will be described with reference toFIGS. 9A to 9F.

First, the base80is prepared. The base80includes the substrate81and the underlayer82. Next, as shown inFIG. 9A, the trap-reinforcing member90is formed on one surface of the underlayer82. The trap-reinforcing member90is laminated by, for example, a sputtering method, a chemical vapor deposition (CVD) method, or the like. The trap-reinforcing member90grows in an island shape. When a film is formed under a condition that the thickness of the trap-reinforcing member90is equal to or less than the thickness at which the trap-reinforcing member90becomes a layer, the trap-reinforcing member90grows into a nucleus and has an island shape. The condition that the thickness of the trap-reinforcing member90is equal to or less than the thickness at which the trap-reinforcing member90becomes a layer is a condition that is equal to or less than a condition that the trap-reinforcing member90theoretically has a thickness corresponding to several atomic layers. Even under the condition of a film having a thickness corresponding to several atomic layers being formed theoretically, the islands which are grown into a nucleus are not actually combined, and thus the trap-reinforcing member90is scattered in an island shape. Also, for example, when the trap-reinforcing member90is selected in consideration of the difference in the surface energy with respect to the underlayer82, the trap-reinforcing member90is formed in an island shape.

Next, as shown inFIG. 9B, the insulating layer91is laminated on one surface of the trap-reinforcing member90. The insulating layer91covers the surfaces of the base body80and the trap-reinforcing member90. As a result, the first surface70A of the intermediate body70has the concavity and convexity.

Next, as shown inFIG. 9C, the magnetic body28is laminated on one surface of the intermediate body70. The first surface28A of the magnetic body28has the concavity and convexity which reflect the shape of the first surface70A of the intermediate body70.

Further, as shown inFIG. 9D, the anisotropic sputtering may be performed when the magnetic body28is laminated. The first surface28A of the magnetic body28is planarized with respect to the first surface70A of the intermediate body70.

Next, as shown inFIG. 9E, the first surface28A of the magnetic body28is planarized. The planarization is performed by, for example, chemical mechanical polishing, dry etching, wet etching, or the like. As shown inFIG. 9D, when the first surface28A is planarized by another method, the planarizing process may not be performed.

Next, as shown inFIG. 9F, the magnetic body29is laminated on the first surface28A of the magnetic body28. The magnetic body28and the magnetic body29are the same. The magnetic body28and the magnetic body29are combined to form the magnetic recording layer20.

Next, as shown inFIG. 9E, the non-magnetic layer30and the first ferromagnetic layer10are sequentially laminated on one surface of the magnetic recording layer20. Then, the unnecessary portions of the non-magnetic layer30and the first ferromagnetic layer10are removed by photolithography or the like. With such a procedure, the magnetic domain wall movement type magnetic recording element101according to the second embodiment can be manufactured.

In the magnetic domain wall movement type magnetic recording element101according to the embodiment, the trap-reinforcing member90is covered with the insulating layer91. The insulating layer91electrically separates the magnetic recording layer20from the base body80. Therefore, the degree of freedom in selecting the trap-reinforcing member90is increased. Thus, the controllability of the movement of the magnetic domain wall21can be further enhanced as compared with the magnetic domain wall movement type magnetic recording element100of the first embodiment.

Although an example of the second embodiment has been described in detail, the second embodiment is not limited to this example, and various modifications and changes may be made within the scope of the present invention described in the appended claims. For example, the second embodiment can employ the same modified example as the first embodiment.

FIG. 10is a cross-sectional view schematically showing Modified Example 2 of the magnetic domain wall movement type magnetic recording element according to the second embodiment. A magnetic domain wall movement type magnetic recording element101A according to Modified Example 2 is different from the magnetic domain wall movement type magnetic recording element100shown inFIG. 1in that the adjacent trap-reinforcing members90are combined with each other and a layer is formed. The trap-reinforcing member90is a layer having concavity and convexity. The insulating layer91reflects the surface shape of the trap-reinforcing member90. Therefore, the first surface70A of the intermediate body70has the concave-convex structure74. Also in this case, the second surface20B of the magnetic recording layer20has the concave-convex structure24, and the same effect as in the magnetic domain wall movement type magnetic recording element101can be obtained.

The magnetic domain wall movement type magnetic recording element101A according to Modified Example 2 is manufactured by continuing the film formation until islands are combined with each other when the trap-reinforcing member90is laminated.

Third Embodiment

FIGS. 11 and 12are schematic cross-sectional views of magnetic domain wall movement type magnetic recording elements according to a third embodiment. The magnetic domain wall movement type magnetic recording elements102and103shown inFIGS. 11 and 12are different from the magnetic domain wall movement type magnetic recording element101shown inFIG. 1in that, in the concave-convex structure24of the magnetic recording layer, some of the concave portions or the convex portions (the convex portions or the concave portions having a second shape) have different shapes from other concave portions or convex portions (the convex portions or the concave portions having a first shape). When the first shape is a convex portion, the second shape is a convex portion, and when the first shape is a concave portion, the second shape is a concave portion. The same parts as those of the magnetic domain wall movement type magnetic recording element according to the first embodiment are designated by the same reference numerals, and description thereof will be omitted. Hereinafter, a case in which the first shape is the convex portion25and the second shape is the convex portion24awill be described as an example.

In the magnetic domain wall movement type magnetic recording element102shown inFIG. 11, the convex portion25having the second shape (hereinafter, referred to as a first convex portion25) in the concave-convex structure24of the magnetic recording layer20is larger than the convex portion24ahaving the first shape in the xz cross section in the extending direction (the x direction, a first direction) of the magnetic recording layer. Therefore, since the first convex portion25has a larger volume than the other convex portions24a, the intensity of a generated magnetic field is large, and the movement of the magnetic domain wall21can be more strongly restricted than by the other convex portion24a. In plan view from the z direction, at least a part of the first convex portion25is located inward from the first ferromagnetic layer10and overlaps an end surface of the first ferromagnetic layer10. When the end surface of the first ferromagnetic layer10is inclined, the end surface may overlap any part of the end surface. In plan view, when the entire first convex portion25is located inward from the first ferromagnetic layer10and overlaps the end surface of the first ferromagnetic layer10, the movement range of the magnetic domain wall21is controlled to be within a range which overlaps the first ferromagnetic layer10. The resistance value of the magnetic domain wall movement type magnetic recording element102changes due to the difference in the magnetization state between the first ferromagnetic layer10and the magnetic recording layer20. Even when the magnetic domain wall21moves to a position at which it does not overlap the first ferromagnetic layer10, a change in the resistance value does not occur. That is, it is possible to suppress the magnetic domain wall21from reaching a portion that does not affect the change in the resistance value by controlling the movement range of the magnetic domain wall21. Further, the range of the change in the resistance value of the magnetic domain wall movement type magnetic recording element102can be specified by defining the movement range of the magnetic domain wall21.

In the magnetic domain wall movement type magnetic recording element103shown inFIG. 12, a convex portion26having the second shape (hereinafter, referred to as a second convex portion26) in the concave-convex structure24of the magnetic recording layer20is larger than the convex portion24ahaving the first shape in the xz cross section in the thickness direction (the z direction) of the magnetic recording layer. Therefore, since the second convex portion26has a larger volume than the other convex portion24a, the intensity of a generated magnetic field is large, and the movement of the magnetic domain wall21can be more strongly restricted than by the other convex portion24a. In plan view from the z direction, at least a part of the second convex portion26is located inward from the first ferromagnetic layer10and overlaps an end surface of the first ferromagnetic layer10. Thus, the movement range of the magnetic domain wall21can be controlled, and it is possible to suppress the magnetic domain wall21from reaching a portion that does not affect the change in the resistance value. Further, the range of the change in the resistance value of the magnetic domain wall movement type magnetic recording element103can be specified by defining the movement range of the magnetic domain wall21.

Here, although the volumes of the convex portions25and26having the second shape and the convex portion24ahaving the first shape are compared, the comparison may be made based on areas of the convex portions25and26having the second shape and the convex portion24ahaving the first shape in the xz cross section. The difference in the intensity of the magnetic field in the x direction controls the movement of the magnetic domain wall21in the x direction. Therefore, even when the volume is constant, the movement range of the magnetic domain wall21can be restricted when there is a difference between the convex portions25and26having the second shape and the convex portion24ahaving the first shape in the xz cross section.

In the magnetic domain wall movement type magnetic recording elements102and103according to the third embodiment, the trapping function can be locally strengthened at positions of the convex portions larger than other convex portions, such as the first convex portion25and the second convex portion26, and thus the movement speed of the magnetic domain wall21in the vicinity thereof can be largely changed. Therefore, when electric resistance and the like are continuously measured while the magnetic domain wall21is moved, a change point occurs in measurement data, and a position of the magnetic domain wall21below the first ferromagnetic layer10can be detected from this change point.

The change in the resistance value of the magnetic domain wall movement magnetic recording elements102and103occurs when the magnetic domain wall21is present at a position at which it overlaps the first ferromagnetic layer10in plan view. The concave portion or the convex portion of the second shape having a strong trapping function is preferably located at a position at which it overlaps the first ferromagnetic layer10in plan view in the lamination direction L of the recording part60. Further, the concave or convex portion having the second shape is preferably disposed inward from an end portion of the first ferromagnetic layer10in the x direction and more preferably overlaps the end portion of the first ferromagnetic layer10. When there is the concave or convex portion of the second shape having the strong trapping function at a position at which it overlaps both ends of the first ferromagnetic layer10in the x direction, an upper limit and a lower limit of the change in the resistance value are easily determined. That is, a start point and an end point of the multi-valued recording can be clarified, and reliability of data of the magnetic domain wall movement type magnetic recording elements102and103can be improved.

Although changing of the shape of the convex portion in the cross sections of the magnetic domain wall movement type magnetic recording elements102and103has been described, for example, the shape of the convex portion may be changed in plan view shape in the lamination direction L. Further, as a method other than changing the shape, for example, even when the trap-reinforcing member90shown in the second embodiment is provided only in some of the concave portions, the same effect as when the shape of the convex portion is changed can be obtained. Furthermore, even when the trap-reinforcing members90are provided in all the concave portions and only the trap-reinforcing members90provided in some of the concave portions are made of a material having a relatively strong trapping function, the same effect can be obtained.

Fourth Embodiment

FIG. 13is a schematic cross-sectional view of a magnetic domain wall movement type magnetic recording element according to a fourth embodiment. The magnetic domain wall movement type magnetic recording element104shown inFIG. 13is different from the magnetic domain wall movement type magnetic recording element100shown inFIG. 1in that a second ferromagnetic layer50which reflects the magnetization state of the magnetic recording layer20is provided between the magnetic recording layer20and the non-magnetic layer30. The same parts as those of the magnetic domain wall movement type magnetic recording element100according to the first embodiment are designated by the same reference numerals, and description thereof will be omitted. The constitution of the magnetic domain wall movement type magnetic recording element according to the fourth embodiment can be applied to any of the elements according to the first to third embodiments.

The second ferromagnetic layer50includes a magnetic body. The same magnetic body as that of the first ferromagnetic layer10can be used for a magnetic body constituting the second ferromagnetic layer50.

The second ferromagnetic layer50is adjacent to the magnetic recording layer20. The magnetization of the second ferromagnetic layer50is magnetically coupled to the magnetization of the magnetic recording layer20. Therefore, the second ferromagnetic layer50reflects a magnetic state of the magnetic recording layer20. When the second ferromagnetic layer50and the magnetic recording layer20are ferromagnetically coupled, the magnetic state of the second ferromagnetic layer50becomes the same as the magnetization state of the magnetic recording layer20, and when the second ferromagnetic layer50and the magnetic recording layer20are antiferromagnetically coupled, the magnetic state of the second ferromagnetic layer50is opposite to the magnetization state of the magnetic recording layer20.

When the second ferromagnetic layer50is inserted between the magnetic recording layer20and the non-magnetic layer30, functions of the second ferromagnetic layer50and the magnetic recording layer20in the magnetic domain wall movement type magnetic recording element104can be separated. The MR ratio of the magnetic domain wall movement type magnetic recording element104is caused by a change in the magnetization state of two magnetic bodies (the first ferromagnetic layer10and the second ferromagnetic layer50) which sandwich the non-magnetic layer30. Therefore, the second ferromagnetic layer50can mainly have a function of improving the MR ratio, and the magnetic recording layer20can mainly have a function of moving the magnetic domain wall21.

When the functions of the second ferromagnetic layer50and the magnetic recording layer20are separated, the degree of freedom of the magnetic body constituting each increases. The second ferromagnetic layer50can be made of a material which provides a coherent tunnel effect with the first ferromagnetic layer10, and the magnetic recording layer20can be made of a material which reduces the movement speed of the magnetic domain wall.

As described above, also in the magnetic domain wall movement type magnetic recording element104according to the fourth embodiment, the same effect as that in the first embodiment can be obtained. Further, the degree of freedom in selecting materials used for the layers can be increased by inserting the second ferromagnetic layer50. In addition, the MR ratio of the magnetic domain wall movement type magnetic recording element104can be further increased by increasing the degree of freedom in selecting materials.

Fifth Embodiment

FIG. 14is a schematic plan view of a magnetic domain wall movement type magnetic recording element105according to a fifth embodiment in which “a configuration having a plurality of recording parts60” is added to the second embodiment. The magnetic domain wall movement type magnetic recording element105shown inFIG. 14is different from the magnetic domain wall movement type magnetic recording element101shown inFIG. 8in that a plurality of recording parts60are provided. The same parts as those of the magnetic domain wall movement type magnetic recording element101according to the second embodiment are designated by the same reference numerals, and description thereof will be omitted. The configuration of the magnetic domain wall movement type magnetic recording element105according to the fifth embodiment can be applied to any of the elements of the other embodiments.

The magnetic domain wall movement type magnetic recording element105shown inFIG. 14has a plurality of recording parts60which extend substantially parallel to each other in the x direction (the first direction). The plurality of recording parts60are arranged at predetermined intervals in a second direction (the y direction inFIG. 14) which intersects the x direction. The plurality of recording parts60are formed on the control unit75which spreads in the xy plane. Further, the trap-reinforcing member90extends over the plurality of recording parts60. For example, the trap-reinforcing member90extends to be in communication with the inside of the concave portion24bconstituting each of the recording parts and to cross the magnetic recording layer20in a direction intersecting the x direction.

The respective recording parts60are preferably disposed so that the concave-convex structures24(the positions of the convex portions24aand the concave portions24b) of the respective magnetic recording layers20overlap each other in plan view in the y direction. The trap-reinforcing member90can be formed linearly in the y direction. Further, in this case, a distance between the trap sites of the adjacent magnetic recording layers (between the convex portions24a) can be made uniform, and an amount of movement of the magnetic domain wall with respect to a pulse input can be made uniform. That is, it becomes easy to simultaneously control the movement of the magnetic domain wall21in each of the plurality of recording parts60.

Since the trap-reinforcing member90is present over the plurality of recording parts60, the multi-valued recording can be performed in each of the recording parts60in the same manner That is, a multi-valued signal generated for each of the recording parts60can be changed evenly. The difference in signal strength between the recording parts60is reduced by making a threshold for recording data in each of the recording parts60constant. As a result, noise of the magnetic domain wall movement type magnetic recording element105as a whole is reduced, and multi-valued recording of data can be stably performed.

As described above, although the magnetic domain wall movement type magnetic recording element according to the embodiment has been described in detail with reference to the drawings, each of the constitutions and the combination thereof in each of the embodiments is an example, and addition, omission, substitution, and other changes of the constitution are possible without departing from the gist of the present invention.

FIG. 15is a cross-sectional view schematically showing Modified Example 3 of the magnetic domain wall movement type magnetic recording element according to the fifth embodiment. A magnetic domain wall movement type magnetic recording element105A according to Modified Example 3 is different from the magnetic domain wall movement type magnetic recording element105in that the trap-reinforcing members90are not linear but are scattered in the xy plane.

The trap-reinforcing member90is scattered irregularly in the xy plane. The plurality of recording parts60are formed on the trap-reinforcing member90which spreads in the xy plane. The trap-reinforcing member90spreads over the plurality of recording parts60in the xy plane.

The movement of the magnetic domain wall21in each of the recording parts60is controlled by the trap-reinforcing member90which spreads in the xy plane. When the trap-reinforcing member90is scattered irregularly, the movement of the magnetic domain wall21becomes irregular. Further, the magnetic domain wall21is inclined in the y direction. Since a data change in each of the recording parts60becomes irregular, the magnetic domain wall movement type magnetic recording element105A is excellent in analog recording of data. Further, when the trap-reinforcing member90forms a layer, the “trap-reinforcing member90” can be replaced with the “convex portion of the trap-reinforcing member90”.

Sixth Embodiment

FIG. 16is a plan view of a magnetic recording array200according to a sixth embodiment. In the magnetic recording array200shown inFIG. 16, the recording parts60of the magnetic domain wall movement type magnetic recording element have a 3×3 matrix arrangement.FIG. 16is an example of a magnetic recording array, and the type, number, and arrangement of the recording parts60are arbitrary. Further, the control part may be provided to be present over all the recording parts60, or may be provided for each of the recording parts60.

The magnetic domain wall movement type magnetic recording element100is connected to one word line WL1to WL3, one bit line BL1to3, and one read line RL1to RL3.

A pulse current is applied to the magnetic recording layer20of an arbitrary recording part60by selecting the word lines WL1to WL3and the bit lines BL1to BL3to which a current is applied, and a write operation is performed. In addition, a current flows in the lamination direction of the arbitrary recording part60by selecting the read lines RL1to RL3and the bit lines BL1to BL3to which a current is applied, and a reading operation is performed. The word lines WL1to WL3, the bit lines BL1to BL3, and the read lines RL1to RL3to which a current is applied can be selected by a transistor or the like. Since each of the recording parts60records information in multiple values, a high-capacity magnetic recording array can be realized.

Although the embodiments have been described in detail, the present invention is not limited to a specific embodiment, and various modifications and changes may be made within the scope of the present invention described in the appended claims.

REFERENCE SIGNS LIST