Magnetic resistance effect element

Abstract

A magnetic resistance effect element is provided. The magnetic resistance effect element includes: a laminate including a first ferromagnetic layer, a second ferromagnetic layer, and a nonmagnetic layer; and an insulating layer covering at least a part of a side surface of the laminate and containing an insulator, the first ferromagnetic layer having a first non-nitrided region and a first nitrided region containing nitrogen closer to the insulating layer than the first non-nitrided region.

Description

Technical Field

[0001] This invention relates to magnetoresistive elements. Background Technology

[0002] A magnetoresistive element is a device whose resistance varies along its stacking direction due to the magnetoresistive effect. A magnetoresistive element comprises two ferromagnetic layers and a non-magnetic layer sandwiched between them. A magnetoresistive element using a conductor in the non-magnetic layer is called a giant magnetoresistive (GMR) element, and a magnetoresistive element using an insulating layer (tunnel barrier layer, barrier layer) in the non-magnetic layer is called a tunnel magnetoresistive (TMR) element. Magnetoresistive elements can be applied to various uses such as magnetic sensors, high-frequency components, magnetic heads, and non-volatile random access memory (MRAM) (e.g., Patent Documents 1 and 2). For example, Patent Document 3 describes a method for controlling the orientation of magnetization using the spin-transmitted torque (STT) generated by a current flowing through the stacking direction of the magnetoresistive element. This method is called a spin-injection magnetization reversal method.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 5586028

[0006] Patent Document 2: Japanese Patent No. 5988019

[0007] Patent Document 3: Japanese Patent Application Publication No. 2015-156501 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] To facilitate magnetization reversal, it is desirable to reduce the energy required for magnetization reversal.

[0010] The present invention was made in view of the above circumstances, and its object is to provide a magnetoresistive effect element capable of magnetization reversal with low energy.

[0011] Technical solutions for solving technical problems

[0012] A magnetoresistive element of the first aspect comprises a laminate and an insulating layer. The laminate comprises a first ferromagnetic layer, a second ferromagnetic layer, and a non-magnetic layer. The insulating layer covers at least a portion of the side surface of the laminate. The first ferromagnetic layer has a first non-nitrided region and a first nitrided region. The first nitrided region is closer to the insulating layer than the first non-nitrided region. The first nitrided region contains nitrogen.

[0013] Invention Effects

[0014] The magnetoresistive element of the present invention can perform magnetization reversal with little energy. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of the magnetoresistive effect element according to the first embodiment.

[0016] Figure 2 This is a top view of the magnetoresistive effect element according to the first embodiment.

[0017] Figure 3 This is a cross-sectional view of the magnetoresistive effect element in the first modified example.

[0018] Figure 4 This is a cross-sectional view of the magnetoresistive effect element in the second variation.

[0019] Figure 5 This is a cross-sectional view of the magnetoresistive effect element in the third variation.

[0020] Figure 6 This is a cross-sectional view of the magnetic recording element used in Example 1.

[0021] Figure 7 This is a cross-sectional view of the magnetic recording element in Application Example 2.

[0022] Figure 8 This is a cross-sectional view of the magnetic recording element used in Example 3.

[0023] Figure 9 This is a cross-sectional view of the domain wall moving element in Application Example 4.

[0024] Figure 10 This is a cross-sectional view of the high-frequency device in Application Example 5.

[0025] Explanation of reference numerals in the attached figures

[0026] 1…First ferromagnetic layer

[0027] 1A…First non-nitrided region

[0028] 1B…First Nitriding Region

[0029] 2…Second ferromagnetic layer

[0030] 2A…Second non-nitrided region

[0031] 2B…Second nitriding region

[0032] 3…Non-magnetic layer

[0033] 3A…Third non-nitrided region

[0034] 3B…Third nitriding region

[0035] 5…Layered bodies

[0036] 6…Insulation layer

[0037] 6B…nitrided region

[0038] 8…Spin-orbit torque wiring

[0039] 10, 11, 12… Magnetoresistive elements

[0040] 21… Resistance measuring instrument

[0041] 22… power supply

[0042] 23… Measurement Department

[0043] 24…First magnetization fixation layer

[0044] 25…Second magnetization fixing layer

[0045] 26…DC power supply

[0046] 27…Inductor

[0047] 28… capacitors

[0048] 29… Output Port

[0049] 30, 31... wiring

[0050] 100, 101, 102… magnetic recording elements

[0051] 103…Magnetic domain wall moving element

[0052] 104…High-frequency devices

[0053] DW…Magnetic domain walls

[0054] Al…First Magnetic Region

[0055] A2…Second magnetic region Detailed Implementation

[0056] The present embodiment will now be described in detail with appropriate reference to the accompanying drawings. In the drawings used in the following description, for ease of understanding of the features of the embodiment, sometimes the characteristic parts are shown enlarged, and sometimes the dimensional ratios of the structural elements differ from the actual dimensions. The materials, dimensions, etc., illustrated in the following description are examples, and the present invention is not limited to these; it can be appropriately modified and implemented without changing its essence.

[0057] Figure 1 This is a cross-sectional view of the magnetoresistive effect element 10 according to the first embodiment. Figure 2 This is a top view of the magnetoresistive effect element 10 according to the first embodiment.

[0058] Below, the stacking direction of each layer is called the Z direction, the direction of each layer's expansion and its position in the plane is called the X direction, and the direction orthogonal to the X direction is called the Y direction.

[0059] Figure 1 The magnetoresistive element 10 shown has a laminate 5 and an insulating layer 6. The plan view of the laminate 5 is, for example, circular. The plan view of the laminate 5 is not limited to a circle, but can also be rectangular, elliptical, oval, etc. The insulating layer 6 covers at least a portion of the side surface of the laminate 5. The insulating layer 6, for example, surrounds the periphery of the laminate 5.

[0060] The magnetoresistive element 10 comprises a first ferromagnetic layer 1, a second ferromagnetic layer 2, and a non-magnetic layer 3. The magnetoresistive element 10 outputs a change in resistance as a change in the relative angle between the magnetization of the first ferromagnetic layer 1 and the magnetization of the second ferromagnetic layer 2.

[0061] The first ferromagnetic layer 1 contains a ferromagnetic material. The magnetization of the first ferromagnetic layer 1 is, for example, more mobile than the magnetization of the second ferromagnetic layer 2. Under the application of a specified external force, the orientation of the magnetization of the second ferromagnetic layer 2 remains unchanged (constant), while the orientation of the magnetization of the first ferromagnetic layer 1 changes. The first ferromagnetic layer 1 is a magnetization-free layer.

[0062] The first ferromagnetic layer 1 has a first non-nitrided region 1A and a first nitrided region 1B. The first nitrided region 1B is located outside the first non-nitrided region 1A. The first nitrided region 1B is closer to the insulating layer 6 than the first non-nitrided region 1A. The first nitrided region 1B is, for example, an annular region surrounding the first non-nitrided region 1A.

[0063] The first non-nitrided region 1A is a region free of nitrogen. Nitrogen-free means that the amount of nitrogen detected by energy-dispersive X-ray spectrophotometry using a transmission electron microscope (TEM) is below the detection limit. The first non-nitrided region 1A is, for example, a conductive ferromagnetic material.

[0064] The first non-nitrided region 1A contains, for example, a metal selected from Cr, Mn, Co, Fe, and Ni; an alloy containing one or more of these metals; or an alloy containing these metals and at least one of the elements selected from B, C, and N. Examples of the first non-nitrided region 1A include Co-Fe, Co-Fe-B, Ni-Fe, Co-Ho alloys, Sm-Fe alloys, Fe-Pt alloys, Co-Pt alloys, and CoCrPt alloys.

[0065] The first non-nitrided region 1A can also be a Whistler alloy. Whistler alloys contain intermetallic compounds with a chemical composition of XYZ or X2YZ. X is a transition metal or noble metal element from the Co, Fe, Ni, or Cu group in the periodic table; Y is a transition metal from the Mn, V, Cr, or Ti group, or an element of X; and Z is a typical element from groups III to V. Examples of Whistler alloys include Co2FeSi, Co2FeGe, Co2FeGa, Co2MnSi, and Co2Mn. 1-a Fe a Al b Si 1-b Co2FeGe 1-c Ga c Etc. Whistler alloys have high spin polarization.

[0066] The first nitrided region 1B is a nitrogen-containing ferromagnetic material. The first nitrided region 1B is conductive. If the first nitrided region 1B is nitrided, the saturation magnetization decreases compared to the case where the first nitrided region 1B is not nitrided. That is, the first ferromagnetic layer 1 becomes more susceptible to magnetization reversal.

[0067] The first nitrided region 1B contains, for example, the same material and nitrogen element as the first non-nitrided region 1A. The first nitrided region 1B is, for example, a nitride or oxynitride of the same material as the first non-nitrided region 1A. The first nitrided region 1B is conductive.

[0068] The first nitrided region 1B is, for example, a nitride or oxide containing one or more elements selected from Ni, Co, and Fe. Any of the nitrides from Ni, Co, and Fe has covalent bonds. These nitrides prevent interdiffusion of elements between the first ferromagnetic layer 1 and the insulating layer 6, and maintain the conductivity of the first ferromagnetic layer 1.

[0069] The width w1 of the first nitrided region 1B is, for example, less than 3 nm. The first nitrided region 1B is, for example, located on the outer side of a position 3 nm inside the outer side of the first ferromagnetic layer 1.

[0070] The second ferromagnetic layer 2 contains a ferromagnetic material. When a specified external force is applied, the orientation of the magnetization of the second ferromagnetic layer 2 remains unchanged. The second ferromagnetic layer 2 is a magnetization-fixed layer.

[0071] The difference in coercivity between the first ferromagnetic layer 1 and the second ferromagnetic layer 2 can be controlled, for example, by adjusting the thicknesses of the first ferromagnetic layer 1 and the second ferromagnetic layer 2. For instance, if the thickness of the first ferromagnetic layer 1 is set to be thinner than the thickness of the second ferromagnetic layer 2, then the coercivity of the first ferromagnetic layer 1 becomes smaller than that of the second ferromagnetic layer 2.

[0072] Alternatively, the coercivity can be improved by setting the second ferromagnetic layer 2 as a synthetic antiferromagnetic structure (SAF structure). The synthetic antiferromagnetic structure consists of two magnetic layers sandwiching a non-magnetic layer. For example, the second ferromagnetic layer 2 can also be a stack comprising a ferromagnetic layer, a spacer layer, and a ferromagnetic layer. By antiferromagnetically coupling the two ferromagnetic layers constituting the SAF structure, the coercivity of the second ferromagnetic layer 2 increases compared to the non-SAF structure. The magnetic layers constituting the SAF structure may contain, for example, ferromagnetic materials, or antiferromagnetic materials such as IrMn and PtMn. The spacer layer may contain, for example, at least one selected from Ru, Ir, and Rh.

[0073] The second ferromagnetic layer 2 has a second non-nitrided region 2A and a second nitrided region 2B. The second nitrided region 2B is located outside the second non-nitrided region 2A. The second nitrided region 2B is closer to the insulating layer 6 than the second non-nitrided region 2A. The second nitrided region 2B is, for example, an annular region surrounding the second non-nitrided region 2A.

[0074] The second non-nitrided region 2A is a nitrogen-free region. The second non-nitrided region 2A is, for example, a conductive ferromagnetic material. The second non-nitrided region 2A can be made of the same material as the first non-nitrided region 1A. The second non-nitrided region 2A can also be made of the same composition as the first non-nitrided region 1A.

[0075] The second nitrided region 2B is a nitrogen-containing ferromagnetic material. The second nitrided region 2B is conductive. If the second nitrided region 2B is nitrided, the leakage magnetic field from the second nitrided region 2B is smaller compared to the case where the second nitrided region 2B is not nitrided, which can reduce the unwanted bias magnetic field applied to the first ferromagnetic layer 1.

[0076] The second nitrided region 2B contains, for example, the same material and nitrogen element as the second non-nitrided region 2A. The second nitrided region 2B is, for example, a nitride or oxynitride of the same material as the second non-nitrided region 2A. The second nitrided region 2B is, for example, electrically conductive.

[0077] The second nitrided region 2B is, for example, a nitride or oxide containing one or more elements selected from Ni, Co, and Fe. Any of the nitrides from Ni, Co, and Fe has covalent bonds. These nitrides prevent interdiffusion of elements between the second ferromagnetic layer 2 and the insulating layer 6, and maintain the conductivity of the second ferromagnetic layer 2.

[0078] The width w2 of the second nitrided region 2B is, for example, 3 nm or less. The second nitrided region 2B is, for example, located on the outer side of a position 3 nm from the outer surface of the second ferromagnetic layer 2. The width w2 of the second nitrided region 2B is, for example, narrower than the width w1 of the first nitrided region 1B. If the nitrided region is narrow, the saturation magnetization of the ferromagnetic layer is less likely to decrease. If the above relationship is satisfied, the magnetization stability of the second ferromagnetic layer 2, which serves as a magnetization fixation layer, can be ensured, and the reversal current density of the first ferromagnetic layer 1, which serves as a magnetization free layer, can be reduced.

[0079] A non-magnetic layer 3 is sandwiched between the first ferromagnetic layer 1 and the second ferromagnetic layer 2. The non-magnetic layer 3 has a thickness, for example, between 0.5 nm and 10 nm. The non-magnetic layer 3 hinders the magnetic coupling between the first ferromagnetic layer 1 and the second ferromagnetic layer 2.

[0080] The non-magnetic layer 3 has a third non-nitrided region 3A and a third nitrided region 3B. The third nitrided region 3B is located outside the third non-nitrided region 3A. The third nitrided region 3B is closer to the insulating layer 6 than the third non-nitrided region 3A. The third nitrided region 3B is, for example, an annular region surrounding the third non-nitrided region 3A.

[0081] The third non-nitrided region 3A is a region that does not contain nitrogen. The third non-nitrided region 3A is, for example, a non-magnetic material.

[0082] The third non-nitrided region 3A can also be a conductor, semiconductor, or insulator.

[0083] When the third non-nitrided region 3A is a metal, the material used is, for example, a metal or alloy containing any element selected from Cu, Au, Ag, Al, and Cr. When the third non-nitrided region 3A is a semiconductor, materials such as Si, Ge, CuInSe2, CuGaSe2, and Cu(In,Ga)Se2 can be used.

[0084] When the third non-nitrided region 3A is an insulator, its material may, for example, contain any one of the spinel structure oxides represented by MgO, Al2O3, and AB2O4. In the spinel structure oxide represented by AB2O4, A is at least one of Mg and Zn, and B is at least one of Al, Ga, and In. The spinel structure oxide represented by AB2O4 is, for example, MgAl2O4. When the nonmagnetic layer 3 is an insulator, the nonmagnetic layer 3 is called a tunnel barrier layer.

[0085] The third nitrided region 3B is a non-magnetic material containing nitrogen. If the third nitrided region 3B is nitrided, oxygen diffusion into the insulating layer 6 can be prevented, even if the third non-nitrided region 3A is an oxide.

[0086] The third nitriding region 3B contains, for example, the same material and nitrogen element as the third non-nitriding region 3A. The third nitriding region 3B is, for example, a nitrogen oxide made of the same material as the third non-nitriding region 3A.

[0087] The width w3 of the third nitrided region 3B is, for example, wider than the width w1 of the first nitrided region 1B and the width w2 of the second nitrided region 2B. The magnetic anisotropy of the first nitrided region 1B is lower than that of the first non-nitrided region 1A, and the magnetic anisotropy of the second nitrided region 2B is lower than that of the second non-nitrided region 2A. Therefore, the spin polarization of the current passing through the first nitrided region 1B and the second nitrided region 2B is low. If the third nitrided region 3B protrudes inward more than the first nitrided region 1B and the second nitrided region 2B, the spin polarization current with low spin polarization applied to the first ferromagnetic layer 1 can be reduced.

[0088] The laminate 5 may also have layers other than the first ferromagnetic layer 1, the second ferromagnetic layer 2, and the non-magnetic layer 3 described above. For example, a base layer may be present below the lamination surface of the laminate 5, and a capping layer may be present on the upper part of the laminate 5. The base layer and the capping layer improve the orientation of the crystallization of the first ferromagnetic layer 1 and the second ferromagnetic layer 2. The base layer may be, for example, a compound with a (001) orientation NaCl structure. The compound with a NaCl structure may be, for example, a nitride containing at least one element selected from Ti, Zr, Nb, V, Hf, Ta, Mo, W, B, Al, Ce, or an oxide containing at least one element selected from Mg, Al, Ce. The capping layer may also contain, for example, one or more metallic elements, alloys of these metallic elements, or laminates containing two or more of these metallic elements, such as Ru, Ir, Ta, Ti, Al, Au, Ag, Pt, Cu, Cr, Mo, W, and Pd. In addition, a buffer layer may be present between the first ferromagnetic layer 1 and the non-magnetic layer 3 or between the second ferromagnetic layer 2 and the non-magnetic layer 3. Buffer layers, such as NiAl layers, improve the lattice matching of these interfaces.

[0089] Insulating layer 6 covers the periphery of the laminate 5. Insulating layer 6 is an insulating layer that insulates the wiring connections and components within the multilayer wiring. Insulating layer 6 is, for example, silicon oxide (SiO2). x ), silicon nitride (SiN) x Silicon carbide (SiC), chromium nitride (CrN), silicon carbonitride (SiCN), silicon oxynitride (SiON), aluminum oxide (Al2O3), silicon alumina (AlSiO), zirconium oxide (ZrO) x ), magnesium oxide (MgO), aluminum nitride (AlN), tantalum oxide (TaO), titanium oxide (TiO), etc.

[0090] The insulating layer 6 may also have a nitrided region 6B in the portion that is in contact with the laminate 5. The nitrided region 6B may be, for example, the aforementioned nitride, oxynitride, etc. The nitrided region 6B has insulating properties.

[0091] Next, the manufacturing method of the magnetoresistive element 10 will be described. First, a substrate is prepared as the base for film formation. The substrate can be crystalline or amorphous. Examples of crystalline substrates include single crystal metal oxide, single crystal silicon, and single crystal sapphire. Examples of amorphous substrates include single crystal silicon with a thermal oxide film, glass, ceramic, and quartz.

[0092] Next, a ferromagnetic layer forming the second ferromagnetic layer 2, a nonmagnetic layer forming the nonmagnetic layer 3, and a ferromagnetic layer forming the first ferromagnetic layer 1 are sequentially stacked on the substrate. The layer forming the second ferromagnetic layer 2 can be formed directly on the substrate or formed above the substrate via an insulating layer, etc. Each layer can be formed by, for example, sputtering, chemical vapor deposition, evaporation, laser ablation, or molecular beam epitaxy (MBE).

[0093] Next, a protective film is formed on a portion of the upper part of these laminated films. Furthermore, the laminated films are processed into a predetermined shape via the protective film. This processing can be performed using methods such as photolithography or ion polishing. The laminated films are processed to form a laminate 5, with the sides of the laminate 5 exposed.

[0094] Next, nitrogen plasma treatment is performed. During nitrogen plasma treatment, the sides of the laminate 5 are nitrided to form a first nitrided region 1B, a second nitrided region 2B, and a third nitrided region 3B.

[0095] When controlling the widths w1, w2, and w3 of the first nitrided region 1B, the second nitrided region 2B, and the third nitrided region 3B, the laminated films are not processed all at once, but rather the first ferromagnetic layer 1, the non-magnetic layer 3, and the second ferromagnetic layer 2 are processed sequentially. By performing nitrogen plasma treatment each time each layer is removed, the widths w1, w2, and w3 of the first nitrided region 1B, the second nitrided region 2B, and the third nitrided region 3B can be controlled. For example, by performing elemental analysis while performing the polishing process, processing can be stopped, for instance, when only the ferromagnetic layer that constitutes the first ferromagnetic layer 1 is removed.

[0096] In addition, the method of forming nitrided regions by performing nitrogen plasma treatment has been described here, but it is also possible to perform grinding and nitriding simultaneously by containing nitrogen in the gas used for grinding, such as argon (Ar), krypton (Kr), or xenon (Xe).

[0097] Next, the insulating layer 6 is used to fill the area around the laminate 5. The insulating layer 6 is formed, for example, by sputtering, chemical vapor deposition, or evaporation.

[0098] Next, the laminate 5 is annealed. The annealing temperature is, for example, below 300°C, or above 250°C and below 300°C.

[0099] If the laminate is annealed, the crystallization of the first ferromagnetic layer 1 and the second ferromagnetic layer 2 is advanced. Additionally, nitrogen from a portion of the first nitrided region 1B, the second nitrided region 2B, and the third nitrided region 3B diffuses into the insulating layer 6, forming a nitrided region 6B. Through these steps, the magnetoresistive element 10 of the first embodiment can be fabricated.

[0100] The magnetoresistive element 10 of this embodiment has a first nitrided region 1B in the first ferromagnetic layer 1, which can reduce the saturation magnetization of the first ferromagnetic layer 1 and reduce the energy required to reverse the magnetization of the first ferromagnetic layer 1. For example, the magnetoresistive element 10 has a low reversal current density required to reverse the magnetization of the first ferromagnetic layer 1.

[0101] In addition, the magnetoresistive effect element 10 of this embodiment has a second nitrided region 2B through the second ferromagnetic layer 2, which can reduce the unwanted bias magnetic field applied to the first ferromagnetic layer 1.

[0102] Furthermore, the magnetoresistive effect element 10 of this embodiment has a third nitrided region 3B through the non-magnetic layer 3, which can prevent the mutual diffusion of elements between the insulating layer 6 and the non-magnetic layer 3 and improve the MR ratio of the magnetoresistive effect element 10.

[0103] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, each structure and combination thereof in each embodiment is an example, and additions, omissions, substitutions and other changes to the structure can be made without departing from the spirit of the present invention.

[0104] Figure 3 This is a cross-sectional view of the magnetoresistive effect element 11 in the first modified example. The difference between the magnetoresistive effect element 11 and the magnetoresistive effect element 10 is that the non-magnetic layer 3 does not have a third nitrided region 3B. In the magnetoresistive effect element 11, the same symbols are used for structures identical to those in the magnetoresistive effect element 10, and the descriptions are omitted.

[0105] The non-magnetic layer 3 is the same as the third non-nitrided region 3A described above. The non-magnetic layer 3 may contain, for example, any one of spinel-structured oxides represented by MgO, Al2O3, or AB2O4. In this case, the nitrided region 6B of the insulating layer 6 is formed in the portion adjacent to the first ferromagnetic layer 1 and the second ferromagnetic layer 2.

[0106] The magnetoresistive effect element 11 of the first variation achieves the same effect as the magnetoresistive effect element 10 of the first embodiment.

[0107] Figure 4This is a cross-sectional view of the magnetoresistive effect element 12 in the second variation. The magnetoresistive effect element 12 differs from the magnetoresistive effect element 10 in that the non-magnetic layer 3 does not have a third nitrided region 3B, and the second ferromagnetic layer 2 does not have a second nitrided region 2B. In the magnetoresistive effect element 12, structures identical to those in the magnetoresistive effect element 10 are labeled with the same symbols, and descriptions are omitted.

[0108] The non-magnetic layer 3 is the same as the third non-nitrided region 3A described above. The non-magnetic layer 3 contains, for example, any one of spinel-structured oxides represented by MgO, Al2O3, or AB2O4. The second ferromagnetic layer 2 is the same as the second non-nitrided region 2A described above. In this case, the nitrided region 6B of the insulating layer 6 is formed in the portion adjacent to the first ferromagnetic layer 1.

[0109] The magnetoresistive element 12 of the second variation achieves the same effect as the magnetoresistive element 10 of the first embodiment.

[0110] Figure 5 This is a cross-sectional view of the magnetoresistive effect element 13 in the third variation. The cross-sectional shape of the stack 5 of the magnetoresistive effect element 13 is different from that of the magnetoresistive effect element 10. In the magnetoresistive effect element 13, the same symbols are used for structures that are the same as those in the magnetoresistive effect element 10, and the descriptions are omitted.

[0111] The perimeter of the laminate 5 gradually increases from the upper surface to the lower surface. In the xz section, the side surface of the laminate 5 is inclined relative to the z direction.

[0112] The magnetoresistive element 13 of the third variation achieves the same effect as the magnetoresistive element 10 of the first embodiment.

[0113] The magnetoresistive element 10 described above can be used for a variety of applications. For example, the magnetoresistive element 10 can be applied in magnetic heads, magnetic sensors, magnetic storage devices, high-frequency filters, etc.

[0114] Next, an application example of the magnetoresistive effect element of this embodiment will be described. Furthermore, in the following application examples, the magnetoresistive effect element 10 is used, but the magnetoresistive effect element is not limited to this.

[0115] Figure 6 This is a cross-sectional view of the magnetic recording element 100 in Application Example 1. Figure 6 It is a cross-sectional view of the magnetoresistive element 10 cut along the stacking direction. Figure 6 The figure also shows electrodes E1 and E2 of the magnetoresistive effect element 10.

[0116] like Figure 6 As shown, the magnetic recording element 100 has a magnetic head MH and a magnetic recording medium W. Figure 6In this design, the direction in which the magnetic recording medium W extends is designated as the X direction, and the direction perpendicular to the X direction is designated as the Y direction. The XY plane is parallel to the main surface of the magnetic recording medium W. The direction connecting the magnetic recording medium W and the magnetic head MH, i.e., the direction perpendicular to the XY plane, is designated as the Z direction.

[0117] The air bearing surface (or media-opposing surface) S of the magnetic head MH faces the surface of the magnetic recording medium W. The magnetic head MH moves along the surface of the magnetic recording medium W in the directions of arrows +X and -X from a position a certain distance away. The magnetic head MH has a magnetoresistive element 10 that functions as a magnetic sensor and a magnetic recording section (not shown). A resistance meter 21 measures the resistance value of the magnetoresistive element 10 in the stacking direction via electrodes E1 and E2.

[0118] The magnetic recording unit applies a magnetic field to the recording layer W1 of the magnetic recording medium W, determining the orientation of the magnetization of the recording layer W1. That is, the magnetic recording unit performs magnetic recording on the magnetic recording medium W. The magnetoresistive element 10 reads the magnetization information of the recording layer W1 written by the magnetic recording unit.

[0119] The magnetic recording medium W has a recording layer W1 and a liner layer W2. The recording layer W1 is the part where magnetic recording is performed, and the liner layer W2 is the magnetic circuit (magnetic flux path) that allows the magnetic flux used for writing to flow back to the magnetic head MH. The recording layer W1 records magnetic information with the magnetization orientation in mind.

[0120] The first ferromagnetic layer 1 of the magnetoresistive element 10 is, for example, a magnetized free layer. Therefore, the first ferromagnetic layer 1 exposed on the air bearing surface S is affected by the magnetization recorded on the recording layer W1 of the opposing magnetic recording medium W. For example, in Figure 6 In this case, influenced by the magnetization of the recording layer W1 in the +Z direction, the magnetization direction of the first ferromagnetic layer 1 is also in the +Z direction. Thus, the magnetization directions of the first ferromagnetic layer 1 and the second ferromagnetic layer 2, which serve as magnetization fixation layers, become parallel.

[0121] Here, the resistance when the magnetization orientations of the first ferromagnetic layer 1 and the second ferromagnetic layer 2 are parallel differs from the resistance when the magnetization orientations of the first ferromagnetic layer 1 and the second ferromagnetic layer 2 are antiparallel. The greater the difference between the resistance values ​​in the parallel and antiparallel cases, the greater the MR ratio of the magnetoresistive element 10.

[0122] In the magnetoresistive element 10 of this embodiment, the first ferromagnetic layer 1 is easily magnetized and reversed. Therefore, the magnetization state of the recording layer W1 can be read sensitively.

[0123] There are no particular restrictions on the shape of the magnetoresistive element 10 of the magnetic head MH. For example, in order to avoid the influence of the leakage magnetic field of the magnetic recording medium W on the first ferromagnetic layer 1 of the magnetoresistive element 10, the first ferromagnetic layer 1 can also be disposed at a position away from the magnetic recording medium W.

[0124] Figure 7 This is a cross-sectional view of the magnetic recording element 101 in Application Example 2. Figure 7 This is a cross-sectional view of the magnetic recording element 101 cut along the stacking direction.

[0125] like Figure 7 As shown, the magnetic recording element 101 includes a magnetoresistive element 10, a power supply 22, and a measuring unit 23. The power supply 22 imparts a potential difference in the stacking direction of the magnetoresistive element 10. The power supply 22 is, for example, a DC power supply. The measuring unit 23 measures the resistance value of the magnetoresistive element 10 in the stacking direction.

[0126] When a potential difference is generated between the first ferromagnetic layer 1 and the second ferromagnetic layer 2 by the power supply 22, current flows along the stacking direction of the magnetoresistive effect element 10. The current undergoes spin polarization as it passes through the second ferromagnetic layer 2, becoming a spin-polarized current. This spin-polarized current reaches the first ferromagnetic layer 1 via the non-magnetic layer 3. The magnetization of the first ferromagnetic layer 1 is reversed by the spin-transmitted torque (STT) generated by the spin-polarized current. Due to the change in the relative angle between the orientation of the magnetization of the first ferromagnetic layer 1 and the orientation of the magnetization of the second ferromagnetic layer 2, the resistance value in the stacking direction of the magnetoresistive effect element 10 changes. The resistance value in the stacking direction of the magnetoresistive effect element 10 is read by the measuring unit 23. That is, Figure 7 The magnetic recording element 101 shown is a spin-transmitted torque (STT) type magnetic recording element.

[0127] Figure 7 The magnetic recording element 101 shown can reduce the reversal current density and reduce the energy required for data writing because the first ferromagnetic layer 1 is easily magnetized and reversed.

[0128] Figure 8 This is a cross-sectional view of the magnetic recording element 102 in Application Example 3. Figure 8 This is a cross-sectional view of the magnetic recording element 102 cut along the stacking direction.

[0129] like Figure 8As shown, the magnetic recording element 102 includes a magnetoresistive element 10, a spin-orbit torque wiring 8, a power supply 22, and a measuring unit 23. The spin-orbit torque wiring 8 is, for example, connected to the first ferromagnetic layer 1. The spin-orbit torque wiring 8 extends in one in-plane direction. The power supply 22 is connected to a first end and a second end of the spin-orbit torque wiring 8. In top view, the first and second ends sandwich the magnetoresistive element 10. A write current flows through the power supply 22 along the spin-orbit torque wiring 8. The measuring unit 23 measures the resistance value of the magnetoresistive element 10 in the stacking direction.

[0130] When a potential difference is generated between the first and second ends of the spin-orbit torque wiring 8 through the power supply 22, current flows in the in-plane direction of the spin-orbit torque wiring 8. The spin-orbit torque wiring 8 has the function of generating spin current through the spin hole effect when the current flows. The spin-orbit torque wiring 8 contains, for example, any of the following metals, alloys, intermetallic compounds, metal borides, metal carbides, metal silicides, and metal phosphides that have the function of generating spin current through the spin hole effect when the current flows. For example, the wiring contains a nonmagnetic metal with an atomic number of 39 or higher having d electrons or f electrons in the outermost shell.

[0131] When current flows in the in-plane direction of the spin-orbit torque wiring 8, a spin-hole effect is generated through spin-orbit interaction. The spin-hole effect is the phenomenon that moving spins bend in a direction orthogonal to the direction of current flow. The spin-hole effect generates spin inhomogeneity within the spin-orbit torque wiring 8 and induces a spin flow in the thickness direction of the spin-orbit torque wiring 8. Spin flows are injected from the spin-orbit torque wiring 8 into the first ferromagnetic layer 1.

[0132] The spin injected into the first ferromagnetic layer 1 imparts a spin-orbit torque (SOT) to the magnetization of the first ferromagnetic layer 1. The first ferromagnetic layer 1 is magnetized and reversed due to the SOT. The resistance value in the stacking direction of the magnetoresistive element 10 changes due to the relative angle between the magnetization direction of the first ferromagnetic layer 1 and the magnetization direction of the second ferromagnetic layer 2. The resistance value in the stacking direction of the magnetoresistive element 10 is read by the measuring unit 23. That is, Figure 8 The magnetic recording element 102 shown is a spin-orbit torque (SOT) type magnetic recording element.

[0133] Figure 8 The magnetic recording element 102 shown can reduce the reversal current density and reduce the energy required for data writing because the first ferromagnetic layer 1 is easily magnetized and reversed.

[0134] Figure 9This is a cross-sectional view of the domain wall moving element (domain wall moving type magnetic recording element) in Application Example 4. The domain wall moving element 103 has a magnetoresistive effect element 10, a first magnetization fixing layer 24, and a second magnetization fixing layer 25. The magnetoresistive effect element 10 is composed of a first ferromagnetic layer 1, a second ferromagnetic layer 2, and a non-magnetic layer 3. Figure 9 In this process, the direction in which the first ferromagnetic layer 1 extends is defined as the X direction, the direction perpendicular to the X direction is defined as the Y direction, and the direction perpendicular to the XY plane is defined as the Z direction.

[0135] The first magnetized fixing layer 24 and the second magnetized fixing layer 25 are connected to the first end and the second end of the first ferromagnetic layer 1. The first end and the second end sandwich the second ferromagnetic layer 2 and the non-magnetic layer 3 in the X direction.

[0136] The first ferromagnetic layer 1 is a layer capable of magnetically recording information through changes in its internal magnetic state. The first ferromagnetic layer 1 has a first magnetic region A1 and a second magnetic region A2 internally. The magnetization of the positions in the first ferromagnetic layer 1 that overlap with the first magnetization fixing layer 24 or the second magnetization fixing layer 25 in the Z direction is fixed in one direction. For example, the magnetization of the position overlapping with the first magnetization fixing layer 24 in the Z direction is fixed in the +Z direction, and the magnetization of the position overlapping with the second magnetization fixing layer 25 in the Z direction is fixed in the -Z direction. As a result, magnetic domain walls DW are formed at the boundary between the first magnetic region A1 and the second magnetic region A2. The first ferromagnetic layer 1 is capable of having magnetic domain walls DW internally. Figure 9 The magnetization M of the first magnetic region A1 of the first ferromagnetic layer 1 shown A1 Oriented in the +Z direction, the magnetization M of the second magnetic region A2 A2 Oriented in the -Z direction.

[0137] The domain wall moving element 103 can record data in multiple or continuously according to the position of the domain wall DW of the first ferromagnetic layer 1. The data recorded in the first ferromagnetic layer 1 is read out as the resistance change of the domain wall moving element 103 when a readout current is applied.

[0138] The ratio of the first magnetic region A1 and the second magnetic region A2 in the first ferromagnetic layer 1 changes as the domain wall DW moves. The magnetization of the second ferromagnetic layer 2 is, for example, related to the magnetization M of the first magnetic region A1. A1 In the same direction (parallel), with the magnetization M of the second magnetic region A2 A2 In the opposite direction (anti-parallel). If the domain wall DW moves in the +X direction, the area of ​​the first magnetic region A1, which overlaps with the second ferromagnetic layer 2 when viewed from the Z direction, increases, and the resistance of the domain wall moving element 103 decreases. Conversely, if the domain wall DW moves in the -X direction, the area of ​​the second magnetic region A2, which overlaps with the second ferromagnetic layer 2 when viewed from the Z direction, increases, and the resistance of the domain wall moving element 103 increases.

[0139] The domain walls DW move by a write current flowing through the X direction of the first ferromagnetic layer 1 or by an external magnetic field being applied. For example, when a write current (e.g., a current pulse) is applied along the +X direction of the first ferromagnetic layer 1, electrons flow in the -X direction opposite to the current, thus the domain walls DW move in the -X direction. As the current flows from the first magnetic region A1 toward the second magnetic region A2, the spin-polarized electrons in the second magnetic region A2 magnetize the first magnetic region A1. A1 Magnetization reversal. Magnetization M through the first magnetic region A1 A1 Magnetization reverses, and the domain walls DW move in the -X direction.

[0140] Figure 9 The domain wall moving element 103 shown can reduce the reversal current density and reduce the energy required for data writing because the first ferromagnetic layer 1 is easily magnetized and reversed.

[0141] Figure 10 This is a schematic diagram of the high-frequency device 104 in Application Example 5. (As shown...) Figure 10 As shown, the high-frequency device 104 includes a magnetoresistive element 10, a DC power supply 26, an inductor 27, a capacitor 28, an output port 29, and wiring 30 and 31.

[0142] Wiring 30 connects the magnetoresistive element 10 to the output port 29. Wiring 31 branches from wiring 30, passing through inductor 27 and DC power supply 26 to ground G. DC power supply 26, inductor 27, and capacitor 28 can be any known components. Inductor 27 blocks the high-frequency component of the current, allowing the constant component to pass. Capacitor 28 allows the high-frequency component of the current to pass while blocking the constant component. Inductor 27 is positioned where the flow of high-frequency current is to be suppressed, and capacitor 28 is positioned where the flow of DC current is to be suppressed.

[0143] When an alternating current or an alternating magnetic field is applied to the ferromagnetic layer contained in the magnetoresistive element 10, the magnetization of the first ferromagnetic layer 1 undergoes a precession motion. The magnetization of the first ferromagnetic layer 1 vibrates strongly near the ferromagnetic resonance frequency of the high-frequency current or high-frequency magnetic field applied to the first ferromagnetic layer 1, and hardly vibrates at frequencies far from the ferromagnetic resonance frequency of the first ferromagnetic layer 1. This phenomenon is called the ferromagnetic resonance phenomenon.

[0144] The resistance of the magnetoresistive element 10 changes according to the vibration of the magnetization of the first ferromagnetic layer 1. A DC power supply 26 applies a DC current to the magnetoresistive element 10. The DC current flows in the stacking direction of the magnetoresistive element 10. The DC current flows through wirings 30 and 31, through the magnetoresistive element 10, to ground G. The potential of the magnetoresistive element 10 changes according to Ohm's law. Based on the change in the potential (resistance) of the magnetoresistive element 10, a high-frequency signal is output from the output port 29.

[0145] Figure 10 The high-frequency device 104 shown can reduce the reversal current density and transmit high-frequency signals efficiently because the first ferromagnetic layer 1 is easy to magnetize and reverse.

Claims

1. A magnetoresistive effect element, wherein, have: A laminate comprising a first ferromagnetic layer, a second ferromagnetic layer, and a nonmagnetic layer; and An insulating layer that covers at least a portion of the sides of the laminate. The non-magnetic layer is located between the first ferromagnetic layer and the second ferromagnetic layer. The first ferromagnetic layer has a first non-nitrided region and a first nitrided region containing nitrogen that is closer to the insulating layer than the first non-nitrided region. The second ferromagnetic layer has a second non-nitrided region and a second nitrided region containing nitrogen that is closer to the insulating layer than the second non-nitrided region. The first non-nitrided region has the same composition as the second non-nitrided region, and the first nitrided region has the same composition as the second nitrided region. The width of the second nitrided region is narrower than the width of the first nitrided region.

2. The magnetoresistive effect element according to claim 1, wherein, The first nitrided region is a nitride or nitride containing one or more elements selected from Ni, Co, and Fe.

3. The magnetoresistive effect element according to claim 1, wherein, The second nitrided region is a nitride or nitride containing one or more elements selected from Ni, Co, and Fe.

4. The magnetoresistive effect element according to claim 1, wherein, The non-magnetic layer contains any one of spinel-structured oxides represented by MgO, Al2O3, and AB2O4. In the spinel structure oxide represented by AB2O4, A is at least one of Mg and Zn, and B is at least one of Al, Ga, and In.

5. The magnetoresistive effect element according to claim 1, wherein, The non-magnetic layer has a third non-nitrided region and a third nitrided region that is closer to the insulating layer than the third non-nitrided region and contains nitrogen.

6. The magnetoresistive effect element according to claim 5, wherein, The third nitrided region is a nitrogen oxide containing the elements that constitute the nonmagnetic layer.

7. The magnetoresistive effect element according to claim 1, wherein, The insulating layer contains nitrides in the portion that is in contact with the laminate.

8. The magnetoresistive effect element according to claim 1, wherein, The width of the first nitrided region is less than 3 nm.

9. The magnetoresistive effect element according to claim 1, wherein, The width of the second nitrided region is less than 3 nm.

10. The magnetoresistive effect element according to claim 1, wherein, The non-magnetic layer has a third non-nitrided region and a third nitrided region containing nitrogen that is closer to the insulating layer than the third non-nitrided region. The widths of the first nitrided region and the second nitrided region are each narrower than the width of the third nitrided region.

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