Method for manufacturing magnetoresistive effect element, magnetoresistive effect element, magnetic laminated film, magnetic memory device, and magnetic sensor

Abstract

A magnetoresistive effect element includes a first ferromagnetic layer, a second ferromagnetic layer, a non-magnetic layer, and a base layer. The non-magnetic layer is between the first ferromagnetic layer and the second ferromagnetic layer. The first ferromagnetic layer is between the base layer and the non-magnetic layer. The base layer contains Ta. The first ferromagnetic layer is represented by Co [alpha] Fe [beta] X [gamma] Pt [delta], X being boron or carbon, satisfying [alpha] + [beta] + [gamma] + [delta] = 1, [alpha] > = [beta] > 0, and [delta] < = 0.3. The easy magnetization axis direction of the first ferromagnetic layer is a first direction in a plane perpendicular to the lamination direction, and the anisotropic field in the second direction of the first ferromagnetic layer is 50 Oe or higher. The second direction is perpendicular to the stacking direction and the first direction.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a magnetoresistive effect element, a magnetoresistive effect element, a magnetic laminate film, a magnetic storage device, and a magnetic sensor. Background Art

[0002] A magnetoresistive element is an element whose resistance value changes in the stacking direction due to the magnetoresistive effect. A magnetoresistive element consists of two ferromagnetic layers and a nonmagnetic layer sandwiched between them. A magnetoresistive element that uses a conductor in the nonmagnetic layer is called a giant magnetoresistive (GMR) device, while one that uses an insulating layer (tunnel barrier layer, potential barrier layer) in the nonmagnetic layer is called a tunnel magnetoresistive (TMR) device. Magnetoresistive elements are used in a variety of applications, such as magnetic sensors, high-frequency components, magnetic heads, and non-volatile random access memory (MRAM).

[0003] The resistance of a magnetoresistive element changes depending on the relative angular difference between the magnetization directions of the two magnetic films. Magnetic storage devices record this resistance value as data. Magnetic sensors use this change in resistance for sensing. If the resistance of a magnetoresistive element unexpectedly changes due to influences such as heat or external magnetic fields, this resistance change becomes noise in the magnetic storage device or sensor. To reduce this noise, efforts are underway to improve the magnetization stability of magnetoresistive elements.

[0004] For example, Patent Document 1 describes how to increase the uniaxial magnetic anisotropy of a magnet by adjusting the crystal grain orientation of a nanocrystalline soft magnetic material. For example, Patent Document 2 describes how to increase the uniaxial magnetic anisotropy of a magnet by adjusting an FePt alloy.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-118040

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2004-311925 Summary of the Invention

[0009] (1) Technical issues to be resolved

[0010] The uniaxial magnetic anisotropy of a ferromagnetic layer is determined by a variety of factors. For example, factors influencing the magnetic anisotropy include anisotropy caused by the shape of the ferromagnetic layer (shape magnetic anisotropy), anisotropy caused by the interface between the ferromagnetic layer and adjacent layers (interface magnetic anisotropy), anisotropy caused by the crystal structure of the ferromagnetic layer (crystalline magnetic anisotropy), and anisotropy caused by the magnetic field during the growth of the ferromagnetic layer (induced magnetic anisotropy). Depending on the application of the magnetoresistive element, the shape and other factors may be limited, making it difficult to achieve shape magnetic anisotropy in the ferromagnetic layer.

[0011] The present disclosure is proposed in response to the above situation and aims to provide a magnetoresistive effect element, a magnetic stacked film, a magnetic storage device and a magnetic sensor that are not easily affected by external forces such as heat and external magnetic fields and have high magnetization stability, as well as methods for manufacturing these elements.

[0012] (2) Technical solution

[0013] The present disclosure provides the following means for solving the above-mentioned problems.

[0014] (1) The method for manufacturing the magnetoresistive element of the first embodiment comprises: a lamination step of laminating a base layer, a first ferromagnetic layer, a non-magnetic layer, and a second ferromagnetic layer in this order; and a magnetic field application annealing step of annealing while applying a magnetic field in a first direction perpendicular to the lamination direction. The base layer comprises Ta. The first ferromagnetic layer comprises Co. α Fe β X γ Pt δ It means that X is boron or carbon, and satisfies α+β+γ+δ=1, α≥β>0, and δ≤0.3.

[0015] (2) In the method for manufacturing the magnetoresistive effect element of the above-described embodiment, the annealing temperature in the magnetic field application annealing step may be 200° C. or higher.

[0016] (3) In the method for manufacturing the magnetoresistive effect element of the above-described embodiment, the annealing time in the magnetic field application annealing step may be 30 minutes or longer.

[0017] (4) In the magnetic field application annealing step of the method for manufacturing the magnetoresistive effect element of the above-described embodiment, the intensity of the applied magnetic field may be 1 kOe or higher.

[0018] (5) In the method for manufacturing the magnetoresistive effect element of the above embodiment, γ may satisfy 0.05≤γ≤0.2.

[0019] (6) In the method for manufacturing the magnetoresistive effect element of the above embodiment, δ may satisfy 0.05≤δ≤0.3.

[0020] (7) In the method of manufacturing the magnetoresistive effect element of the above-described embodiment, the nonmagnetic layer may include magnesium and oxygen.

[0021] (8) The magnetoresistance effect element of the second embodiment includes a first ferromagnetic layer, a second ferromagnetic layer, a non-magnetic layer, and a base layer. The non-magnetic layer is located between the first ferromagnetic layer and the second ferromagnetic layer. The first ferromagnetic layer is located between the base layer and the non-magnetic layer. The base layer contains Ta. The first ferromagnetic layer is made of Co. α Fe β X γ Pt δ denoted as , X is boron or carbon, satisfies α + β + γ + δ = 1, α ≥ β > 0, and δ ≤ 0.3. The easy axis of the first ferromagnetic layer is oriented in a first direction in a plane perpendicular to the stacking direction, and the anisotropy field of the first ferromagnetic layer in a second direction is 50 Oe or greater. The second direction is perpendicular to the stacking direction and the first direction.

[0022] (9) In the magnetoresistive effect element of the above embodiment, γ may satisfy 0.05≤γ≤0.2.

[0023] (10) In the magnetoresistive effect element of the above embodiment, δ may satisfy 0.05≤δ≤0.3.

[0024] (11) In the magnetoresistive effect element of the above-described embodiment, the nonmagnetic layer may include magnesium and oxygen.

[0025] (12) In the magnetoresistance effect element of the above-described embodiment, the thickness of the first ferromagnetic layer may be 2 nm or more and 20 nm or less.

[0026] (13) In the magnetoresistive effect element of the above embodiment, the uniaxial magnetic anisotropy energy of the first ferromagnetic layer may be 2.0×10 4 erg / cm or greater.

[0027] (14) The magnetoresistance effect element of the above embodiment may further include a first electrode and a second electrode, wherein the first electrode is connected to a first end of the base layer and the second electrode is connected to a second end of the base layer different from the first end.

[0028] (15) In the magnetoresistive effect element of the above embodiment, when viewed from above in the stacking direction, the width of the first ferromagnetic layer in the first direction may be not less than 90% and not more than 110% of the width of the first ferromagnetic layer in the second direction.

[0029] (16) The magnetic laminate film of the third embodiment includes a base layer and a first ferromagnetic layer. The base layer is in contact with one side of the first ferromagnetic layer. The base layer contains Ta. The first ferromagnetic layer is made of Co. α Fe β X γ Pt δdenoted by , where X is boron or carbon, satisfies α+β+γ+δ=1, α≥β>0, 0.05≤γ≤0.2, and 0.05≤δ≤0.3. The easy axis of the first ferromagnetic layer is in a first direction in a plane perpendicular to the stacking direction, and the anisotropy field of the first ferromagnetic layer in a second direction is 50 Oe or greater. The second direction is perpendicular to the stacking direction and the first direction.

[0030] (17) The magnetic storage device of the fourth embodiment has the magnetoresistive effect element of the above-described embodiment.

[0031] (18) The magnetic sensor of the fifth embodiment has the magnetoresistive effect element of the above-described embodiment.

[0032] (3) Beneficial effects

[0033] The magnetoresistive effect element, the magnetic laminated film, the magnetic storage device, and the magnetic sensor disclosed herein can reduce the influence of external force. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a cross-sectional view of the magnetoresistive effect element of the first embodiment.

[0035] Figure 2 is a plan view of the magnetoresistive effect element of the first embodiment.

[0036] Figure 3 Schematic diagram of a method for manufacturing the magnetoresistive effect element according to the first embodiment.

[0037] Figure 4 Schematic diagram of a method for manufacturing the magnetoresistive effect element according to the first embodiment.

[0038] Figure 5 FIG. 4 is a circuit diagram of the magnetic storage device of this embodiment.

[0039] Figure 6 FIG. 1 is a cross-sectional view of a magnetoresistive element used in the magnetic storage device of this embodiment.

[0040] Figure 7 FIG. 1 is a circuit diagram of another example of the magnetic storage device of this embodiment.

[0041] Figure 8 is a schematic diagram of the magnetic sensor of this embodiment.

[0042] Figure 9 Schematic diagram of the magnetic stacked film of this embodiment.

[0043] Description of Reference Numerals

[0044] 1. 91: first ferromagnetic layer; 2. 92: second ferromagnetic layer; 3. 93: non-magnetic layer; 4. 5. 94: base layer; 6: first electrode; 7: second electrode; 10. 11: magnetoresistance effect element; 20: magnetic laminate film; 101: first switch; 102: second switch; 103: third switch; 104: fourth switch; 105: detector; 110. 111: magnetic storage device; 120: magnetic sensor; L1: first wiring; L2: second wiring; L3: third wiring; L4: fourth wiring; L5: fifth wiring; Wx, Wy: width. DETAILED DESCRIPTION

[0045] The following describes embodiments of the present invention in detail with reference to the accompanying drawings. The drawings used in the following description may include features that are enlarged for clarity, and the dimensional ratios of various components may differ from their actual sizes. The materials, dimensions, and other examples given in the following description are merely illustrative, and the present invention is not limited to these examples. The present invention may be implemented with appropriate modifications within the scope of achieving the desired effects of the present invention.

[0046] First, let's define directions. The stacking direction of each layer is the Z direction. The plane direction perpendicular to the Z direction is the X direction. The X direction is an example of a first direction. The direction perpendicular to the Z and X directions is the Y direction. The Y direction is an example of a second direction. The Z direction is the direction from the base layer to the first ferromagnetic layer, +Z is the direction toward the first ferromagnetic layer, and -Z is the opposite direction. In the following description, the +Z direction is sometimes expressed as "upward" and the -Z direction is expressed as "downward." Up and down do not necessarily coincide with the direction of gravity.

[0047] Magnetoresistive element

[0048] Figure 1 1 is a cross-sectional view of a magnetoresistance effect element 10 according to the first embodiment. The magnetoresistance effect element 10 includes a first ferromagnetic layer 1 , a second ferromagnetic layer 2 , a nonmagnetic layer 3 , and a base layer 4 .

[0049] The magnetoresistance effect element 10 outputs the change in the relative angle of the magnetization of the first ferromagnetic layer 1 and the second ferromagnetic layer 2 as a change in resistance or output voltage. For example, the magnetization of the first ferromagnetic layer 1 is easier to move than the magnetization of the second ferromagnetic layer 2. When a predetermined external force is applied, the magnetization direction of the second ferromagnetic layer 2 does not change (is fixed), but the magnetization direction of the first ferromagnetic layer 1 does change. The resistance value of the magnetoresistance effect element 10 changes as the magnetization direction of the first ferromagnetic layer 1 changes relative to the magnetization direction of the second ferromagnetic layer 2. In this case, the second ferromagnetic layer 2 is sometimes referred to as a magnetization-fixed layer, and the first ferromagnetic layer 1 is referred to as a non-magnetization layer. The following explanation assumes that the second ferromagnetic layer 2 is a magnetization-fixed layer and the first ferromagnetic layer 1 is a non-magnetization layer, but this relationship can be reversed.

[0050] The difference in mobility between the magnetization of the first ferromagnetic layer 1 and the magnetization of the second ferromagnetic layer 2 when a predetermined external force is applied results from a difference in coercivity between the first ferromagnetic layer 1 and the second ferromagnetic layer 2. For example, if the second ferromagnetic layer 2 is thicker than the first ferromagnetic layer 1, the coercivity of the second ferromagnetic layer 2 is generally greater than that of the first ferromagnetic layer 1. Furthermore, for example, if the second ferromagnetic layer 2 is formed into a synthetic antiferromagnetic structure (SAF structure), the coercivity of the second ferromagnetic layer 2 can be greater than that of the first ferromagnetic layer 1. A synthetic antiferromagnetic structure includes two magnetic layers sandwiched by a spacer layer. When the two magnetic layers sandwiched by the spacer layer are antiferromagnetically coupled, the coercivity of the magnetic layers is greater than when they are not antiferromagnetically coupled. The spacer layer includes at least one element selected from the group consisting of Ru, Ir, and Rh.

[0051] The first ferromagnetic layer 1 is located between the base layer 4 and the non-magnetic layer 3. The first ferromagnetic layer 1 is made of Co α Fe β X γ Pt δ The ferromagnetic layer represented by Co satisfies α+β+γ+δ=1. α Fe β X γ Pt δ The first ferromagnetic layer 1 has an in-plane magnetic anisotropy. For example, the first ferromagnetic layer 1 has a cubic (bcc) structure.

[0052] α represents the composition ratio of Co, and β represents the composition ratio of Fe. α and β satisfy α ≥ β > 0. When α > β, the first ferromagnetic layer 1 becomes a cobalt-rich ferromagnetic layer. Cobalt is a material that exhibits uniaxial anisotropy more readily than iron. Iron tends to adopt a cubic lattice structure, while cobalt tends to adopt a hexagonal lattice structure. Therefore, the first ferromagnetic layer 1, which is richer in cobalt than iron, exhibits greater uniaxial magnetic anisotropy.

[0053] X is boron (B) or carbon (C), preferably boron (B). γ represents the composition ratio of X. Preferably, γ satisfies 0.05≤γ≤0.2. When γ satisfies this range, the lattice matching between the first ferromagnetic layer 1 and the non-magnetic layer 3 increases, and the uniaxial magnetic anisotropy of the first ferromagnetic layer 1 increases. For example, the lattice matching between the first ferromagnetic layer 1 and the non-magnetic layer 3 is within 10%, preferably within 5%. The lattice matching degree indicates the degree of deviation of the lattice constant of one layer on both sides of the interface when the lattice constant of the other layer is used as a reference. The lower the lattice matching degree on both sides of the interface, the higher the lattice matching degree. When the lattice constant of the non-magnetic layer 3 is used as a reference, the lattice constant of the first ferromagnetic layer 1 is, for example, not less than 90% and not more than 110% of the lattice constant of the non-magnetic layer 3.

[0054] δ represents the composition ratio of platinum. It satisfies δ≤0.3. δ=0 is also possible. When δ=0, the first ferromagnetic layer 1 is composed of Coα Fe β X γ It is indicated by . It is best to satisfy 0.05≤δ≤0.3. When δ>0, the uniaxial magnetic anisotropy of the first ferromagnetic layer 1 increases. It is believed that the increase in the uniaxial magnetic anisotropy of the first ferromagnetic layer 1 is due to the inclusion of Pt with a large spin-orbit interaction in the first ferromagnetic layer 1.

[0055] The easy magnetization axis of the first ferromagnetic layer 1 is oriented in the X direction. The anisotropy field of the first ferromagnetic layer 1 in the Y direction is 50 Oe or greater. The anisotropy field of the first ferromagnetic layer 1 in the Y direction is preferably 70 Oe or greater, more preferably 100 Oe or greater, even more preferably 200 Oe or greater, and particularly preferably 280 Oe or greater. The first ferromagnetic layer 1 has a large magnetic anisotropy along one direction in the XY plane. This large magnetic anisotropy is achieved by performing annealing in a magnetic field as described below.

[0056] The thickness of the first ferromagnetic layer 1 is, for example, 2 nm or more and 20 nm or less. When the thickness of the first ferromagnetic layer 1 is within this range, the uniaxial magnetic anisotropy of the first ferromagnetic layer 1 becomes large.

[0057] Figure 2 This is a plan view of the magnetoresistive effect element 10 of the first embodiment as viewed from the Z direction. The planar shape of the first ferromagnetic layer 1 as viewed from the Z direction can be circular or rectangular. The planar shape of the first ferromagnetic layer 1 as viewed from the Z direction can be isotropic. The width Wx of the first ferromagnetic layer 1 in the X direction is, for example, 90% or more and 110% or less of the width Wy of the first ferromagnetic layer 1 in the Y direction. In addition, the width of the first ferromagnetic layer 1 in the long axis direction is, for example, 110% or less of the width in the short axis direction. When the planar shape is isotropic, shape magnetic anisotropy has almost no effect on the first ferromagnetic layer 1. Even if the planar shape as viewed from the Z direction is isotropic, large uniaxial magnetic anisotropy can be achieved by annealing in a magnetic field as described below.

[0058] The planar shape of the first ferromagnetic layer 1 viewed from the Z direction may have anisotropy. For example, the width Wx of the first ferromagnetic layer 1 in the X direction may be greater than 110% of the width Wy of the first ferromagnetic layer 1 in the Y direction. The width of the first ferromagnetic layer 1 in the major axis direction may be greater than 110%, preferably greater than 150%, of the width of the first ferromagnetic layer 1 in the minor axis direction. When the major axis of the first ferromagnetic layer 1 is in the X direction, the shape magnetic anisotropy acts on the magnetization of the first ferromagnetic layer 1, and the uniaxial magnetic anisotropy of the first ferromagnetic layer 1 can be further enhanced. In this case, the anisotropy field of the first ferromagnetic layer 1 in the Y direction can be increased to 350 Oe or higher.

[0059] The uniaxial magnetic anisotropy energy of the first ferromagnetic layer 1 is, for example, 2.0×104 erg / cm or higher, preferably 5.0×10 4 erg / cm or higher, more preferably 1.0×10 5 erg / cm or higher.

[0060] The second ferromagnetic layer 2 faces the first ferromagnetic layer 1 via the nonmagnetic layer 3. The second ferromagnetic layer 2 is an in-plane magnetized film, and its magnetization direction is the same as that of the first ferromagnetic layer 1, and is in one direction in the XY plane.

[0061] For example, the second ferromagnetic layer 2 may be a metal selected from the group consisting of Cr, Mn, Co, Fe, and Ni, or an alloy containing one or more metals selected from these groups, or an alloy containing one or more metals selected from these groups and at least one element selected from the group consisting of B, C, and N. The second ferromagnetic layer 2 may be Co-Fe, Co-Fe-B, Ni-Fe, Co-Ho alloy (CoHo2), or Sm-Fe alloy (SmFe 12 The second ferromagnetic layer 2 may be a ferromagnetic material having the same composition as the first ferromagnetic layer 1. The second ferromagnetic layer 2 may also be a Heusler alloy.

[0062] The nonmagnetic layer 3 is located between the first ferromagnetic layer 1 and the second ferromagnetic layer 2. The thickness of the nonmagnetic layer 3 is, for example, in the range of 1 nm to 10 nm. The nonmagnetic layer 3 suppresses magnetic coupling between the first ferromagnetic layer 1 and the second ferromagnetic layer 2.

[0063] The non-magnetic layer 3 includes, for example, a non-magnetic insulator. Non-magnetic insulators include, for example, Al2O3, SiO2, MgO, MgAl2O4, and materials in which a portion of the Al, Si, or Mg in these materials is replaced by Zn, Be, or the like. These materials have a large band gap and excellent insulating properties. The non-magnetic layer 3 includes, for example, magnesium and oxygen. The non-magnetic layer 3 can be MgO or MgAl2O4. The non-magnetic layer 3 includes magnesium and oxygen and has excellent lattice matching with the first ferromagnetic layer 1 and the second ferromagnetic layer 2 adjacent to the non-magnetic layer 3. The lattice matching between the second ferromagnetic layer 2 and the non-magnetic layer 3 is, for example, within 10%, preferably within 5%.

[0064] The non-magnetic layer 3 may be a non-magnetic metal or semiconductor. A non-magnetic metal is a metal or alloy containing any element selected from the group consisting of Cu, Au, Ag, Al, and Cr. Metals or alloys containing these elements have excellent electrical conductivity and reduce the area resistance (hereinafter referred to as RA) of the magnetoresistive element 10. Non-magnetic semiconductors include, for example, Si, Ge, CuInSe2, CuGaSe2, and Cu(In,Ga)Se2.

[0065] The base layer 4 sandwiches the first ferromagnetic layer 1 together with the non-magnetic layer 3. The first ferromagnetic layer 1 is laminated on the base layer 4, for example. The base layer 4 enhances the orientation of the crystals of the first ferromagnetic layer 1 and the second ferromagnetic layer 2.

[0066] The base layer 4 includes Ta. The base layer 4 may include Ta. By annealing in a magnetic field, as described later, the base layer 4 including Ta absorbs boron or carbon in the first ferromagnetic layer 1. When the boron or carbon in the first ferromagnetic layer 1 is absorbed, the crystallinity of the first ferromagnetic layer 1 increases, and the uniaxial magnetic anisotropy of the first ferromagnetic layer 1 increases.

[0067] "Method for manufacturing a magnetoresistive element"

[0068] Figure 3 and Figure 4 1 and 2 are diagrams for explaining a method for manufacturing the magnetoresistive effect element 10 according to the first embodiment. The method for manufacturing the magnetoresistive effect element 10 includes a lamination step, a magnetic field application annealing step, and a processing step.

[0069] Figure 3 This diagram is used to explain the lamination process. In the lamination process, base layer 94, first ferromagnetic layer 91, non-magnetic layer 93, and second ferromagnetic layer 92 are laminated in this order. The layers can be laminated using methods such as sputtering, chemical vapor deposition (CVD), electron beam deposition (EB deposition), and atomic laser deposition.

[0070] The base layer 94 corresponds to the base layer 4 and includes Ta. The first ferromagnetic layer 91 corresponds to the first ferromagnetic layer 1 and includes Co. α Fe β X γ Pt δ α, β, γ, δ, and X in the composition formula are the same as those in the first ferromagnetic layer 1. The nonmagnetic layer 93 corresponds to the nonmagnetic layer 3 and includes, for example, magnesium and oxygen. The second ferromagnetic layer 92 corresponds to the second ferromagnetic layer 2.

[0071] The first ferromagnetic layer 91 before the magnetic field application annealing step is an in-plane magnetization film affected by shape magnetic anisotropy. On the other hand, the first ferromagnetic layer 91 before the magnetic field application annealing step has an isotropic magnetization orientation in the plane and has no uniaxial magnetic anisotropy.

[0072] Figure 4 This is a schematic diagram for explaining magnetic field application annealing. In the magnetic field application annealing step, annealing is performed while applying a magnetic field H in the X direction.

[0073] In the magnetic field application annealing process, the annealing temperature is preferably 200° C. or higher. If the annealing temperature is high while applying the magnetic field H, the crystals of the first ferromagnetic layer 91 are more easily affected by the magnetic field H and more easily oriented to a single magnetization direction.

[0074] In the magnetic field annealing process, the annealing time should be at least 30 minutes and the magnetic field strength should be at least 1 kOe. Applying a sufficiently strong magnetic field makes it easier to align the magnetization direction in a single direction.

[0075] In the magnetic field application annealing step, the easy magnetization axis of the first ferromagnetic layer 1 is oriented in the X direction even before the processing step. Due to the magnetic field application annealing step, the anisotropic magnetic field of the first ferromagnetic layer 1 in the Y direction is 50 Oe or more.

[0076] Next, a processing step is performed. This processing step can be performed using, for example, photolithography. By processing the laminated film into a predetermined shape, the magnetoresistive effect element 10 is obtained. The base layer 94 becomes the base layer 4, the first ferromagnetic layer 91 becomes the first ferromagnetic layer 1, the non-magnetic layer 93 becomes the non-magnetic layer 3, and the second ferromagnetic layer 92 becomes the second ferromagnetic layer 2. In this embodiment, the processing step is performed after the magnetic field application annealing step, but the processing step can also be performed before the magnetic field application annealing step.

[0077] The magnetoresistance effect element 10 of this embodiment has high stability because the magnetization of the first ferromagnetic layer 1 is strongly oriented in the X direction. The magnetoresistance effect element 10 of this embodiment is not susceptible to unexpected magnetization reversal due to external forces, even when heat or an external magnetic field is applied.

[0078] The magnetoresistive effect element 10 of this embodiment can be used as a magnetic storage device, a magnetic sensor, or the like.

[0079] Figure 5 1 is a circuit diagram of a magnetic storage device 110 according to this embodiment. The magnetic storage device 110 includes a plurality of magnetoresistive elements 11, a plurality of first wirings L1, a plurality of second wirings L2, a plurality of third wirings L3, a plurality of first switches 101, a plurality of second switches 102, and a plurality of third switches 103. For example, the magnetic storage device 110 includes the magnetoresistive elements 11 arranged in an array.

[0080] Each wire in the first wiring L1 is used to electrically connect a power source to one or more magnetoresistance effect elements 11. Each wire in the second wiring L2 is used when writing and reading data. Each wire in the second wiring L2 is used to electrically connect a reference potential to one or more magnetoresistance effect elements 11. For example, the reference potential is ground potential. Each wire in the third wiring L3 electrically connects a power source to one or more magnetoresistance effect elements 11. During use, the power source is connected to the magnetic storage device 110.

[0081] Each magnetoresistance effect element 11 is connected to a first switch 101, a second switch 102, and a third switch 103, respectively. The first switch 101 is connected between the magnetoresistance effect element 11 and the first wiring L1. The second switch 102 is connected between the magnetoresistance effect element 11 and the second wiring L2. The third switch 103 is connected between the magnetoresistance effect element 11 and the third wiring L3. Any of the first switch 101, the second switch 102, and the third switch 103 can be shared with the magnetoresistance effect element 11 connected to the same wire. The first switch 101, the second switch 102, and the third switch 103 can each use a known element, such as a transistor.

[0082] Figure 6 FIG1 is a cross-sectional view of a magnetoresistive element 11 used in a magnetic storage device 110 of this embodiment. The magnetoresistive element 10 includes a first ferromagnetic layer 1, a second ferromagnetic layer 2, a nonmagnetic layer 3, a base layer 5, a first electrode 6, and a second electrode 7. The magnetoresistive element 11 is a magnetoresistive element that utilizes spin-orbit torque (SOT) for magnetization reversal and is sometimes also referred to as a spin-orbit torque magnetoresistive element, a spin injection magnetoresistive element, or a spin current magnetoresistive element.

[0083] The first ferromagnetic layer 1, second ferromagnetic layer 2, and non-magnetic layer 3 are identical to those described above. The top surface of the second ferromagnetic layer 2 is connected to the third wiring L3. The base layer 5 is identical to the base layer 4, except that its length in the X direction is longer than its length in the Y direction. The first electrode 6 is connected to a first end of the base layer 5. The first electrode 6 is also connected to the first wiring L1. The second electrode 7 is connected to a second end of the base layer 5. The second electrode 7 is also connected to the second wiring L2. The first electrode 6 and the second electrode 7 are conductors.

[0084] The magnetoresistive element 11 is an element that records and stores data. The magnetoresistive element 11 records data as its resistance in the z-direction. When a write current is applied along the base layer 5, the z-direction resistance of the magnetoresistive element 11 changes as the rotation of the first ferromagnetic layer 1 injected from the base layer 5 changes. The z-direction resistance of the magnetoresistive element 11 can be read by applying a read current between the second ferromagnetic layer 2 and the first electrode 6 or the second electrode 7.

[0085] The first ferromagnetic layer 1 is injected with spins from the base layer 5. The base layer 5 induces a spin current through the spin-orbit interaction and the interfacial Raschbach effect, and injects spins into the first ferromagnetic layer 1. For example, the spin-orbit torque (SOT) provided by the base layer 5 is sufficient to reverse the magnetization of the first ferromagnetic layer 1.

[0086] The spin Hall effect is a phenomenon based on spin-orbit interaction, which generates a spin current perpendicular to the direction of current flow. The spin Hall effect is similar to the ordinary Hall effect in that the direction of motion of a moving charge (electron) is bent. In the ordinary Hall effect, the direction of motion of a charged particle in a magnetic field is bent by the Lorentz force. In contrast, the spin Hall effect can change the direction of spin transfer even in the absence of a magnetic field simply by moving electrons (or allowing current to flow).

[0087] For example, when current flows through the substrate layer 5, the first spin (polarized in one direction) and the second spin (polarized in the opposite direction to the first spin) are each bent in a direction perpendicular to the current direction through the spin Hall effect. For example, the first spin (polarized in the -y direction) is bent from the x-direction (i.e., the direction of motion) to the +z-direction, and the second spin (polarized in the +y direction) is bent from the x-direction (i.e., the direction of motion) to the -z-direction.

[0088] In non-magnetic materials (non-ferromagnetic materials), the number of first-spin electrons and second-spin electrons generated by the Spin Hall Effect is equal. In other words, the number of first-spin electrons moving in the +z direction is equal to the number of second-spin electrons moving in the -z direction. The first and second spins flow in a direction that eliminates the uneven distribution of spins. When the first and second spins move in the z direction, the charge flows cancel each other out, resulting in zero current. Spin currents that do not involve an electric current are specifically called pure spin currents.

[0089] If the electron current of the first spin is expressed as J ↑ The electron current of the second spin is represented by J ↓ The spin current is expressed as J S If J S The definition of J S =J ↑ -J ↓ . Spin current J S The first spin is injected from the base layer 5 into the first ferromagnetic layer 1 .

[0090] The magnetization of the first ferromagnetic layer 1 is affected by the spin-orbit torque (SOT) generated by the injected spins, causing the orientation direction to change. The base layer 5 contains Ta. Ta has a strong spin-orbit interaction, allowing many spins to be injected into the first ferromagnetic layer 1.

[0091] The magnetoresistance effect element 11 has high magnetization stability because the first ferromagnetic layer 1 is oriented in the plane along the X direction. Therefore, the magnetic storage device 110 having this magnetoresistance effect element 11 has high reliability because data is difficult to be rewritten by an unexpected external force.

[0092] Figure 7FIG. 4 is a circuit diagram of another example of the magnetic storage device of this embodiment. Figure 7 The magnetic memory device 111 shown in FIG. 1 includes a plurality of magnetoresistive effect elements 10 , a plurality of fourth wires L4 , a plurality of fifth wires L5 , and a plurality of fourth switches 104 .

[0093] For example, the magnetoresistance effect elements 10 are arranged in a matrix form. Each magnetoresistance effect element 10 is connected to the fourth wire L4 and the fifth wire L5, respectively.

[0094] The current flow through magnetoresistive element 10 is controlled by fourth switch 104. By opening fourth switch 104, magnetoresistive element 10 can be used to write and read data. Magnetoresistive element 10 writes data using spin transfer torque by allowing current to flow in the stacking direction. Fourth switch 104 is similar to first switch 101 and the like.

[0095] The magnetic storage device 111 has a magnetoresistive effect element 10 having a first ferromagnetic layer 1 in which magnetization is strongly oriented in one direction within a plane, so that data is difficult to be rewritten by an unexpected external force and reliability is high.

[0096] Figure 8 1 is a schematic diagram of a magnetic sensor 120 according to this embodiment. The magnetic sensor 120 includes a magnetoresistive element 10 and a detector 105 .

[0097] Detector 105 detects changes in the resistance of magnetoresistive element 10. A first end of detector 105 is connected to base layer 4, and a second end of detector 105 is connected to second ferromagnetic layer 2. When a detection magnetic field to be detected is applied to first ferromagnetic layer 1 of magnetoresistive element 10, the magnetization of first ferromagnetic layer 1 undergoes a pre-spin. When the magnetization of first ferromagnetic layer 1 deflects, the relative angle between the magnetizations of first ferromagnetic layer 1 and second ferromagnetic layer 2 changes, and the resistance of magnetoresistive element 10 also changes accordingly. For example, when magnetic sensor 120 detects leakage magnetic fields generated by magnetization written on a magnetic recording medium, magnetic sensor 120 functions as a magnetic head.

[0098] The magnetic sensor 120 has the magnetoresistive effect element 10 having the first ferromagnetic layer 1 in which magnetization is strongly oriented in one direction within a plane, so data is difficult to be rewritten by an unexpected external force and reliability is high.

[0099] "Magnetic laminated film"

[0100] Figure 9 2 is a cross-sectional view of the magnetic laminate film of this embodiment. The magnetic laminate film 20 includes an underlayer 4 and a first ferromagnetic layer 1. The first ferromagnetic layer 1 is laminated on the underlayer 4. An intermediate layer may be provided between the first ferromagnetic layer 1 and the underlayer 4.

[0101] The first ferromagnetic layer 1 and the base layer 4 are the same as those of the magnetoresistive effect element 10. The base layer 4 may contain Ta and be made of Ta. The first ferromagnetic layer 1 is made of Co α Fe β X γ Pt δ denoted by , where X is boron or carbon, satisfies α+β+γ+δ=1, α≥β>0, 0.05≤γ≤0.2, and 0.05≤δ≤0.3. The easy axis of magnetization of the first ferromagnetic layer is oriented in the X direction, and the anisotropy field of the first ferromagnetic layer in the Y direction is 50 Oe or greater.

[0102] The magnetic stacked film of this embodiment has high magnetization stability because the first ferromagnetic layer 1 is strongly oriented in one direction (X direction) within a plane.

[0103] The magnetic stacked film of this embodiment can also be used as an optical element, utilizing anisotropic magnetic sensors, magneto-dielectric effect, or magnetic Faraday effect.

[0104] Although the examples of the embodiments have been given so far and the preferred aspects of the present invention have been described, the present invention is not limited to these embodiments. For example, the characteristic configuration of each embodiment can be applied to other embodiments.

[0105] [Example]

[0106] "Example 1"

[0107] In Example 1, a magnetoresistive effect element satisfying the following configuration was manufactured.

[0108] Basal layer: Ta

[0109] First ferromagnetic layer: Co with a thickness of 3 nm 0.4 Fe 0.4 B 0.2

[0110] Non-magnetic layer: MgO

[0111] Second ferromagnetic layer: Co 0.2 Fe 0.6 B 0.2

[0112] Plane shape: Square with a length of 10 mm in the X and Y directions

[0113] The magnetoresistive element of Example 1 is fabricated by sequentially stacking a base layer, a first ferromagnetic layer, a nonmagnetic layer, and a second ferromagnetic layer, performing magnetic field annealing, and then processing the element into a predetermined shape. The magnetic field annealing was performed under the following conditions: an annealing temperature of 350°C, an annealing time of 60 minutes, and a magnetic field strength of 10 kOe.

[0114] In Example 1, the magnetization of the first ferromagnetic layer of the magnetoresistive effect element is oriented in the X direction in the plane under zero magnetic field. The anisotropy field in the Y direction of the first ferromagnetic layer is 50 Oe. The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 3.6×10 4 erg / cm.

[0115] "Example 2"

[0116] In Example 2, the composition of the first ferromagnetic layer is Co 0.5 Fe 0.3 B 0.2 , which is different from Example 1. In Example 2, α>β, which is different from Example 1. Other conditions are the same as those in Example 1, and the same measurements as in Example 1 are performed.

[0117] In Example 2, the magnetization of the first ferromagnetic layer of the magnetoresistive element is oriented in the X direction in the plane under zero magnetic field. The anisotropy field of the first ferromagnetic layer in the Y direction is 63 Oe. The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 4.5×10 4 erg / cm.

[0118] "Comparative Example 1"

[0119] The difference between Comparative Example 1 and Example 1 is that the composition of the first ferromagnetic layer is Co 0.2 Fe 0.6 B 0.2 The difference between Comparative Example 1 and Example 1 is that α<β. Other conditions and measurement methods are the same as those in Example 1.

[0120] In Comparative Example 1, the magnetization of the first ferromagnetic layer of the magnetoresistive element is oriented in the X direction in the plane under zero magnetic field. The anisotropy field in the Y direction of the first ferromagnetic layer is 25 Oe. The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 1.7×10 4 erg / cm.

[0121] "Example 3"

[0122] The difference between Example 3 and Example 1 is that the composition of the first ferromagnetic layer is Co 0.36 Fe 0.36 B 0.13 Pt 0.15 The difference between Example 3 and Example 1 is that the first ferromagnetic layer 1 contains Pt with a concentration of δ=0.15. Other conditions and measurement methods are the same as those of Example 1.

[0123] In Example 3, the magnetization of the first ferromagnetic layer of the magnetoresistive element is oriented in the X direction in the plane under zero magnetic field. The anisotropy field of the first ferromagnetic layer in the Y direction is 64 Oe. The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 3.6×10 4 erg / cm.

[0124] "Example 4"

[0125] The difference between Example 4 and Example 3 is that the composition of the first ferromagnetic layer is Co 0.33 Fe 0.33 B 0.13 Pt 0.21 The difference between Example 4 and Example 3 is that δ=0.21. Other conditions and measurement methods are the same as those in Example 3.

[0126] In Example 4, the magnetization of the first ferromagnetic layer of the magnetoresistive effect element is oriented in the X direction in the plane under zero magnetic field. The anisotropy field in the Y direction of the first ferromagnetic layer is 127 Oe. The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 6.9×10 4 erg / cm.

[0127] "Example 5"

[0128] The difference between Example 5 and Example 3 is that the composition of the first ferromagnetic layer is Co 0.31 Fe 0.31 B 0.12 Pt 0.26 The difference between Example 5 and Example 3 is that δ=0.26. Other conditions and measurement methods are the same as those in Example 3.

[0129] In Example 5, the magnetization of the first ferromagnetic layer of the magnetoresistive element is oriented in the X direction in the plane under zero magnetic field. The anisotropy field of the first ferromagnetic layer in the Y direction is 145 Oe. The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 6.3×10 4 erg / cm.

[0130] "Example 6"

[0131] The difference between Example 6 and Example 2 is that the composition of the first ferromagnetic layer is Co 0.46 Fe 0.27 B 0.14 Pt 0.13 The difference between Example 6 and Example 2 is that the first ferromagnetic layer 1 includes Pt with a δ of 0.13. Other conditions are the same as those of Example 2, and the same measurements as those of Example 2 are performed.

[0132] In Example 6, the magnetization of the first ferromagnetic layer of the magnetoresistive element is oriented in the X direction in the plane under zero magnetic field. The anisotropy field in the Y direction of the first ferromagnetic layer is 100 Oe. The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 5.7×10 4 erg / cm.

[0133] "Example 7"

[0134] The difference between Example 7 and Example 6 is that the composition of the first ferromagnetic layer is Co 0.41 Fe 0.26 X 0.13 Pt 0.20 The difference between Example 7 and Example 6 is that δ=0.20. Other conditions and measurement methods are the same as those in Example 6.

[0135] In Example 7, the magnetization of the first ferromagnetic layer of the magnetoresistive effect element is oriented in the X direction in the plane under zero magnetic field. The anisotropy field in the Y direction of the first ferromagnetic layer is 125 Oe. The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 6.6×10 4 erg / cm.

[0136] "Example 8"

[0137] The difference between Example 8 and Example 6 is that the composition of the first ferromagnetic layer is Co 0.38 Fe 0.24 X 0.12 Pt 0.26 The difference between Example 8 and Example 6 is that δ=0.26. Other conditions and measurement methods are the same as those in Example 6.

[0138] In Example 8, the magnetization of the first ferromagnetic layer of the magnetoresistive element is oriented in the X direction in the plane under zero magnetic field. The anisotropy field of the first ferromagnetic layer in the Y direction is 187 Oe. The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 7.7×10 4 erg / cm.

[0139] "Example 9"

[0140] In Example 9, the thickness of the first ferromagnetic layer was 2 nm, which was different from Example 7. Other conditions were the same as those in Example 7, and the same measurements as in Example 7 were performed.

[0141] In Example 9, the magnetization of the first ferromagnetic layer of the magnetoresistive element is oriented in the X direction in the plane under zero magnetic field. The anisotropy field of the first ferromagnetic layer in the Y direction is 89 Oe. The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 3.8×10 4 erg / cm.

[0142] "Example 10"

[0143] The difference between Example 10 and Example 7 is that the thickness of the first ferromagnetic layer is 8 nm. Other conditions and measurement methods are the same as those of Example 7.

[0144] In Example 10, the magnetization of the first ferromagnetic layer of the magnetoresistive effect element is oriented in the X direction in the plane under zero magnetic field. The anisotropy field in the Y direction of the first ferromagnetic layer is 233 Oe. The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 1.4×10 5 erg / cm.

[0145] "Example 11"

[0146] The difference between Example 11 and Example 7 is that the thickness of the first ferromagnetic layer is 20 nm. Other conditions and measurement methods are the same as those of Example 7.

[0147] In Example 11, the magnetization of the first ferromagnetic layer of the magnetoresistive effect element is oriented in the X direction in the plane under zero magnetic field. The anisotropy field in the Y direction of the first ferromagnetic layer is 145 Oe. The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 8.2×10 4 erg / cm.

[0148] "Example 12"

[0149] The difference between Example 12 and Example 11 is that the annealing temperature is set to 300° C. Other conditions and measurement methods are the same as those of Example 11.

[0150] In Example 12, the magnetization of the first ferromagnetic layer of the magnetoresistive element is oriented in the X direction in the plane under zero magnetic field. The anisotropy field of the first ferromagnetic layer in the Y direction is 271 Oe. The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 1.5×10 5 erg / cm.

[0151] "Example 13"

[0152] The difference between Example 13 and Example 11 is that the annealing temperature is set to 250° C. Other conditions and measurement methods are the same as those of Example 11.

[0153] In Example 13, the magnetization of the first ferromagnetic layer of the magnetoresistive element is oriented in the X direction in the plane under zero magnetic field. The anisotropy field of the first ferromagnetic layer in the Y direction is 173 Oe. The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 9.9×10 4 erg / cm.

[0154] The above results are summarized in the following table.

[0155] [Table 1]

[0156]

[0157] As shown in Table 1 above, the uniaxial anisotropy of Examples 1 to 12 is larger than that of Comparative Example 1. Therefore, the magnetoresistance effect elements of Examples 1 to 12 have excellent magnetization stability.

Claims

1. A method for manufacturing a magnetoresistive effect element, have: a step of laminating a base layer, a first ferromagnetic layer, a non-magnetic layer, and a second ferromagnetic layer in sequence, and A magnetic field application annealing step of performing annealing while applying a magnetic field in a first direction in a plane perpendicular to the stacking direction, and The base layer includes Ta, The first ferromagnetic layer is made of Co α Fe β X γ Pt δ express, X is boron or carbon, It satisfies α+β+γ+δ=1, α≥β>0, and δ≤0.

3.

2. The method for manufacturing a magnetoresistive element according to claim 1, The annealing temperature in the magnetic field application annealing step is 200° C. or higher.

3. The method for manufacturing a magnetoresistive element according to claim 1, The annealing time in the magnetic field application annealing step is 30 minutes or longer.

4. The method for manufacturing a magnetoresistive effect element according to claim 1, wherein: The intensity of the magnetic field applied in the magnetic field application annealing step is 1 kOe or higher.

5. The method for manufacturing a magnetoresistive effect element according to claim 1, wherein: γ satisfies 0.05≤γ≤0.

2.

6. The method for manufacturing a magnetoresistive effect element according to claim 1, wherein: δ satisfies 0.05≤δ≤0.

3.

7. The method for manufacturing a magnetoresistive effect element according to claim 1, wherein: The nonmagnetic layer includes magnesium and oxygen.

8. A magnetoresistance effect element, wherein: comprising a first ferromagnetic layer, a second ferromagnetic layer, a non-magnetic layer and a base layer, The non-magnetic layer is located between the first ferromagnetic layer and the second ferromagnetic layer. The first ferromagnetic layer is located between the base layer and the non-magnetic layer. The base layer contains Ta, The first ferromagnetic layer is made of Co α Fe β X γ Pt δ express, X is boron or carbon, Satisfies α+β+γ+δ=1, α≥β>0, and δ≤0.3, The easy magnetization axis direction of the first ferromagnetic layer is a first direction in a plane perpendicular to the stacking direction. The anisotropy field of the first ferromagnetic layer in the second direction is 50 Oe or higher, and The second direction is perpendicular to the stacking direction and the first direction.

9. The magnetoresistive effect element according to claim 8, wherein γ satisfies 0.05≤γ≤0.

2.

10. The magnetoresistive effect element according to claim 8, wherein δ satisfies 0.05≤δ≤0.

3.

11. The magnetoresistive effect element according to claim 8, wherein The nonmagnetic layer includes magnesium and oxygen.

12. The magnetoresistive effect element according to claim 8, wherein The thickness of the first ferromagnetic layer is 2 nanometers or more and 20 nanometers or less.

13. The magnetoresistive effect element according to claim 8, wherein The uniaxial magnetic anisotropy energy of the first ferromagnetic layer is 2.0×10 4 erg / cm or higher.

14. The magnetoresistive effect element according to claim 8, wherein The magnetoresistive effect element further includes a first electrode and a second electrode, The first electrode is connected to the first end of the base layer, and The second electrode is connected to a second end of the base layer that is different from the first end.

15. The magnetoresistive effect element according to claim 8, wherein When viewed in plan from the stacking direction, the width of the first ferromagnetic layer in the first direction is not less than 90% and not more than 110% of the width of the first ferromagnetic layer in the second direction.

16. A magnetic laminate film, wherein: comprising a base layer and a first ferromagnetic layer, The substrate layer contacts one side of the first ferromagnetic layer, The base layer contains Ta, The first ferromagnetic layer is made of Co α Fe β X γ Pt δ express, X is boron or carbon, Satisfies α+β+γ+δ=1, α≥β>0, 0.05≤γ≤0.2, 0.05≤δ≤0.3, The easy magnetization axis direction of the first ferromagnetic layer is a first direction in a plane perpendicular to the stacking direction. The anisotropy field of the first ferromagnetic layer in the second direction is 50 Oe or higher, and The second direction is perpendicular to the stacking direction and the first direction. 17 . A magnetic storage device comprising the magnetoresistive effect element according to claim 8 . 18 . A magnetic sensor comprising the magnetoresistive effect element according to claim 8 .

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