Spin current magnetization rotating element, magnetoresistance effect element, and magnetic memory

Abstract

The present invention provides a method for fabricating a spin-orbit torque wiring layer comprising: a first ferromagnetic layer having a variable magnetization direction; and a spin-orbit torque wiring layer adjacent to the first ferromagnetic layer, the spin-orbit torque wiring layer being made of one or more elements, at least one of which has a crystalline structure, and where the dimensions of the lattice constants of the crystalline structure are represented by a, b, and c, the internal coordinates of atoms occupying a unit cell are (0,0,0), (0.5,0.5,0), (0.25,0.75,0.25), A spin current magnetization rotating element having layers of (0.75, 0.25, 0.25), (0, 0.5, 0.5), (0.5, 0, 0.5), (0.75, 0.75, 0.75), and (0.25, 0.25, 0.75), in which the ab plane is stacked to have a four-fold spiral structure along the c axis, the angle (γ) between the a axis and the b axis is in the range of 60°≦γ≦120°, and the ratio of b to a (b / a) is in the range of 0.2≦b / a≦1.0.

Description

[Technical Field]

[0001] The present invention relates to a spin current magnetization rotating element, a magnetoresistive effect element, and a magnetic memory.This application claims priority to U.S. Provisional Patent Application No. 63 / 439,447, the contents of which are incorporated herein by reference. [Background technology]

[0002] A spin current magnetization rotating element is known that includes a ferromagnetic layer whose magnetization direction is changeable and a spin orbit torque wiring layer adjacent to the ferromagnetic layer.

[0003] For example, U.S. Patent Application Publication No. 2022 / 0,149,269 teaches a spin current magnetization rotator element (spintronics element) that stacks a ferromagnetic layer and an antiferromagnetic layer (spin orbit torque wiring layer) and can reverse the perpendicular magnetization of the ferromagnetic layer by changing the direction of spin polarization of the spin current generated by the direction of current flowing parallel to the plane of the antiferromagnetic layer. U.S. Patent Application Publication No. 2022 / 0,149,269 teaches that by using an inclined antiferromagnetic material such as Mn3Sn as the material for the spin orbit torque wiring layer, it is possible to reverse the direction of spin polarization and change the direction of spin orbit torque by reversing the direction of current flowing in the antiferromagnetic layer without using exchange bias.

[0004] Further examples of spin current magnetization rotation elements, magnetoresistive elements, and magnetic memories are taught in U.S. Patent Application Publication No. 2019 / 0,267,540, in which a spin orbit torque wiring layer having a superparamagnetic material therein allows magnetization rotation even when the current density through the spin orbit torque wiring layer is reduced. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent Application Publication No. 2022 / 0,149,269 [Patent Document 2] U.S. Patent Application Publication No. 2019 / 0,267,540 Summary of the Invention [Means for solving the problem]

[0006] According to one aspect of the present disclosure, a spin current magnetization rotating element includes a first ferromagnetic layer having a variable magnetization direction, and a spin orbit torque wiring layer adjacent to the first ferromagnetic layer, the spin orbit torque wiring layer including one or more elements. At least one of the one or more elements has a crystalline structure, and where the dimensions of the lattice constants of the crystalline structure are represented by a, b, and c, the internal coordinates of atoms occupying a unit cell are (0,0,0), (0.5,0.5,0), (0.25,0.75,0.25), (0.75,0.25,0.25), (0,0.5,0.5), (0.5,0,0.5), (0.75,0.75,0.75), and (0.25,0.25,0.75), the ab plane is stacked to have a four-fold spiral structure along the c axis, the angle (γ) between the a axis and the b axis is within the range of 60°≦γ≦120°, and the ratio of b to a (b / a) is within the range of 0.2≦b / a≦1.0.

[0007] According to another aspect of the present disclosure, a magnetoresistive effect element includes the above-mentioned spin current magnetization rotating element, a second ferromagnetic layer having a fixed magnetization direction, and a non-magnetic layer disposed between the first ferromagnetic layer and the second ferromagnetic layer.

[0008] According to a further aspect of the present disclosure, a magnetic memory includes a plurality of the above-described magnetoresistive effect elements. [Brief explanation of the drawings]

[0009] A more complete understanding of the present disclosure and many of its attendant advantages will be readily obtained by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which: Figure 1 is a cross-sectional view of one embodiment of a spin current magnetization rotator element; Figure 2A is a conceptual diagram illustrating an ABCD stacked structure (a stacked structure having a four-fold spiral axis); Figure 2B is a conceptual diagram illustrating an ACAC stacked structure (a stacked structure having a two-fold spiral axis); Figure 3 is a graph showing the total energy as b / a is changed for the ABCD stacked structure (a stacked structure having a four-fold spiral axis) and the ACAC stacked structure (a stacked structure having a two-fold spiral axis); Figure 4 is a cross-sectional view of one embodiment of a magnetoresistive element; and Figure 5 is a circuit diagram of one embodiment of a magnetic memory. DETAILED DESCRIPTION OF THE INVENTION

[0010] As used herein, terms such as "a" and "an" mean "one or more." When an amount, concentration, or other value or parameter is given as a range and / or the description includes a list of upper and lower limits, this is understood to specifically disclose all integers, fractions, and all ranges formed from any pair of any upper and lower limits within the given range, regardless of whether a smaller range is individually disclosed. When a range of numerical values ​​is described herein, unless otherwise specified, the range is intended to include not only all integers and fractions within the range, but also its endpoints. As an example, the range 1-10 describes and includes all the independent subranges 3.4-7.2, as well as the following list of values: 1, 4, 6, 10, etc.

[0011] In one embodiment of the present disclosure, the spin orbit torque wiring layer has a specific crystal structure, so that when a current is passed through the spin orbit torque wiring layer of the spin current magnetization rotor, a relatively large spin current is obtained. Therefore, when the spin current magnetization rotor is used in a magnetoresistive element or a magnetic memory, the magnetoresistive element and the magnetic memory can be driven with a smaller current.

[0012] One embodiment of each element is described below.

[0013] [Spin ​​current magnetized rotating element]

[0014] 1 is a cross-sectional view showing one embodiment of a spin current magnetization rotating element. On the surface of a spin orbit torque wiring layer 11, a ferromagnetic layer (first ferromagnetic layer) 12 capable of rotatable magnetization is laminated.

[0015] In the spin current magnetization rotating element of the present disclosure, the spin orbit torque wiring layer contains one or more elements, and at least one element in the spin orbit torque wiring layer has a crystal structure in which the internal coordinates of atoms occupying a unit cell are (0,0,0), (0.5,0.5,0), (0.25,0.75,0.25), (0.75,0.25,0.25), (0,0.5,0.5), (0.5,0,0.5), (0.75,0.75,0.75), and (0.25,0.25,0.75), where the dimensions of the lattice constants of the crystal structure are represented by a, b, and c. The ab-plane is stacked to have a four-fold spiral structure along the c-axis, and the angle (γ) between the a-axis and the b-axis is within the range of 60°≦γ≦120°, and the ratio of b to a (b / a) is within the range of 0.2≦b / a≦1.0.

[0016] The range of the angle (γ) is more preferably 80°≦γ≦100°, and even more preferably 85°≦γ≦95°.

[0017] Furthermore, the range of b / a is preferably 0.4≦b / a≦0.6, and more preferably 0.47≦b / a≦0.55.

[0018] In one embodiment, the one or more elements contained in the spin orbit torque wiring layer 11 include an element having an orthorhombic structure with a space group of Fddd.

[0019] In one embodiment, the spin orbit torque wiring layer 11 includes tungsten as one or more elements.

[0020] In one embodiment, the one or more elements contained in the spin orbit torque wiring layer 11 include tungsten having an orthorhombic structure with a space group of Fddd.

[0021] In one embodiment, the thickness of the spin orbit torque wiring layer 11 is 0.1-50 nm, preferably 0.3-20 nm, and more preferably 0.5 nm-10 nm.

[0022] By performing simulations such as those described below, the inventors of the present disclosure have found that when orthorhombic tungsten has an orthorhombic structure with a space group of Fddd, it exhibits a spin Hall conductivity at the Fermi level that is greater than that of α-W or β-W, and that a similar phenomenon is expected for heavy metal elements with atomic numbers equal to or greater than that of yttrium.

[0023] (Simulation method)

[0024] To search for crystal structures exhibiting large spin Hall conductivity (SHC), we performed an evolutionary algorithm (EA) search according to the method described in T. Ishikawa, T. Miyake, and K. Shimizu, Phys. Rev. B 100, 174506 (2019). (i) First, a population of 20 structures was randomly constructed with a fixed number of atoms (N) in the computational cell. All structures were fully optimized using a constant-pressure variable-cell relaxation method and density functional theory (DFT) calculations and ranked by total energy E. (ii) Next, the structures in the population were subjected to the evolutionary operators (EOs) "crossbreeding" and "mutation" to create 20 next-generation structures and optimize them. The crossbreeding operator creates a slab structure based on two randomly selected structures from the population and averages the lattice parameters (a, b, c, α, β, γ) between them, i.e., creates a child with the structural characteristics of the parent. Atoms in the cell were randomly added or removed, leaving the number N. The mutation operator changes six lattice parameters, i.e., the cell distortion, of a structure selected from the population. The ratio of EOs was set so that 10 structures were created by the crossover operator and the remaining 10 structures were created by the mutation operator. (iii) Then, four structures with very low E values ​​before applying EOs were inherited to the next generation. The 24 structures in the newly created population were again ranked according to E, and four unstable structures with very high E values ​​were removed from the population. By repeating steps (ii) and (iii), the structures in the population were gradually updated. Several EA searches were performed by varying N from 2, 3, 4, 5, 6, 8, and 10. The EA code was combined with the Quantum ESPRESSO (QE) code (see P. Giannozzi, at 211., J. Phys. Condens. Matter 21, 395502 (2009)) to optimize the structures created by EOs.The generalized gradient approximation by Perdew, Burke, and Ernzerhof (PBE) was used for the exchange-correlation functional in the framework of the projector augmented wave (PAW) method (see, for example, P.E. Blochl, Phys. Rev. B 50, 17953 (1994), G. Kresse and D. Joubert, Phys. Rev. B 59, 1758 (1999)). The PAW potential was obtained from the QE website (see https: / / www.quantum-espresso.org / ). The energy cutoffs for the wave function and charge density were set to 80 Ry and 640 Ry, respectively. The EA search was performed using an 8x8x8 grid for k-space integration over the Brillouin zone (BZ), and subsequently the k-point sampling number (N) was adjusted to more accurately compare the energies between the predicted structures. k ) was increased. The pressure was set to 0 kbar. To confirm the dynamical stability of the predicted structure, phonon calculations based on density functional perturbation theory implemented in the QE code were performed.

[0025] J s is generated along the x direction and flows along the y direction. c Assuming that spin polarization occurs in the z direction due to SHC(σ xy z ) is calculated by Kubo's formula in the clean limit as follows:

number

number

[0026] Starting with randomly generated structures, an EA search yielded the bcc structure corresponding to the α-phase as the most stable structure, and the Pm-3n structure corresponding to the β-phase as the second most stable structure. Other metastable structures in the evolutionary ensemble were then investigated. To identify structures distinct from α-W and β-W, the X-ray diffraction patterns of the ensemble were simulated using RIETAN-2000 (see F. Izumi and T. Ikeda, Mater. Sci. Forum 321-324, 198). As a result of the comparison, 15 structures distinct from α-W and β-W were obtained. The space groups of the structures were assigned using FINDSYM (see, e.g., H.T. Stokes and D.M. Hatch, J. Appl. Cryst. 38, 237 (2005)). Furthermore, the absolute values ​​of the SHC at the Fermi level (|σ) were calculated for the 15 newly predicted structures (Table 1). xy z (0)|) was calculated.

[0027] Of these structures, the simulation results for the α phase, β phase, and Fddd structure are shown in Table 1.

[0028] Table 1 shows the crystal structures obtained by first-principles calculations and a structure search scheme based on an evolutionary algorithm. The structures of the α and β phases correspond to Im-3m (bcc) and Pm-3n (A15), respectively. p is the number of atoms in the primitive cell, ΔE is the energy relative to α-W, σ xy z (O) is the intrinsic spin Hall conductivity (SHC) at the Fermi level. ε max and σ xy z (ε max ) are the position of the maximum peak from the Fermi level and the SHC value, respectively. σ xy z (0) and σ xy z (ε max ) units are (h / e) (Ωcm) -1 is.

[0029] [Table 1]

[0030] Here, the cell parameters and atomic positions of the Fddd structure are as shown in the table below (Table 2).

[0031] [Table 2]

[0032] As shown in Table 1, when tungsten has an orthorhombic structure with a space group of Fddd, the spin conductivity at the Fermi level is predicted to be greater than that of α-W or β-W.

[0033] Since the Fddd structure is a structure in which a body-centered cubic structure is deformed into a spiral shape, the one or more elements contained in the spin orbit torque wiring layer 11 are not limited to tungsten, and any element having a body-centered cubic structure can be used.

[0034] Examples of elements other than tungsten that can be used in the spin orbit torque wiring layer 11 include tantalum and molybdenum.

[0035] The magnetization direction of the ferromagnetic layer 12 is changeable.

[0036] The magnetization may be parallel or tilted to the layer direction, but is preferably substantially perpendicular to the layer direction. In the present disclosure, "substantially perpendicular" means that the angle is 80 to 100°, preferably 85 to 95°, and more preferably 88 to 92°.

[0037] In one embodiment, the ferromagnetic layer 12 may include one or more metals selected from the group consisting of Co, Fe, Ni, and Gd, alloys of these metals, Heusler alloys such as Cu-Mn-Al alloys and Mn-Cu-Sn alloys, or other ferromagnetic materials, such as oxides like chromium (II) oxide.

[0038] In one embodiment, the ferromagnetic layer is stacked directly on the spin orbit torque wiring layer. In another embodiment, the first ferromagnetic layer is stacked on the spin orbit torque wiring layer via one or more other layers. The first ferromagnetic layer, as a separate layer disposed between the spin orbit torque wiring layers, may be deposited by known deposition methods such as sputtering or epitaxial growth (MBE, MOCVD, etc.), and is not particularly limited. In this case, examples of the one or more other layers include layers containing Cu, Ni, or Ru as materials.

[0039] When a current is passed through the spin orbit torque wiring layer 11 of the spin current magnetization rotating element in a layer-parallel direction (for example, the direction of the horizontal arrow in Figure 1), a spin current is generated in a direction perpendicular to the current due to the spin orbit interaction (spin Hall effect), and spin accumulation occurs that is spin-polarized perpendicular, parallel, or oblique to the interface between the spin orbit torque wiring layer 11 and the ferromagnetic layer 12. This spin accumulation applies a spin orbit torque to the magnetization of the ferromagnetic layer 12, causing magnetization rotation in the ferromagnetic layer 12.

[0040] In the spin current magnetization rotating element of the present disclosure, a relatively large spin current is generated compared to conventional elements, and therefore magnetization rotation is possible even when a current with a low current density is used.

[0041] [Method of manufacturing a spin current magnetization rotating element]

[0042] The spin current magnetization rotating element of the present disclosure can be fabricated by the following procedure: (1) creating a spin orbit torque wiring layer 11, (2) stacking a ferromagnetic layer 12 on the spin orbit torque wiring layer 11, and (3) adding a voltage application mechanism. This will be explained in detail below.

[0043] (1) Creating the spin-orbit torque wiring layer 11

[0044] The spin-orbit torque wiring layer may be fabricated by forming a film of the material of the present disclosure on a substrate by known deposition means such as sputtering or epitaxial growth (MBE, MOCVD, etc.).

[0045] When forming a spin orbit torque wiring layer made of tungsten having an orthorhombic structure with a space group of Fddd, for example, the following methods (a) to (d) may be employed. (a) GaN (1-100) with m-plane is prepared as a substrate. (b) An AlN(1-100) film is formed on top of it. (c) A Zn(1-100) film is formed on top of it. (d) A W(110) film is formed on it.

[0046] Although not intended to limit the present invention, the reason why tungsten having an orthorhombic structure with a space group of Fddd is formed by the above method is thought to be as follows.

[0047] We performed simulation calculations of the total energy for the ABCD stacking structure (four-fold spiral structure) shown in Figure 2A and the ACAC stacking structure (two-fold spiral structure) shown in Figure 2B, with c / a fixed at 2 and b / a varied. Figure 3 shows the relative values ​​when the total energy for the ACAC stacking structure is 0. The horizontal axis represents b / a, and the vertical axis represents the relative value of the total energy for the ACAC stacking structure. For the ACAC stacking structure, b / a = 0.71 corresponds to a body-centered cubic (bcc) lattice. As can be seen from Figure 4, when b / a < 0.55, the Fddd structure (ABCD stacking structure) is more stable than the ACAC stacking structure at the same b / a. Therefore, when tungsten is deformed from b / a = 0.71, corresponding to bcc(110), to around b / a = 0.55, the ABCD stacking structure becomes more stable than the ACAC stacking structure, and an Fddd structure is generated.

[0048] For reference, the lattice constants of α-W(110), Zn(1-100), AlN(1-100), and GaN(1-100) are shown in Table 3.

[0049] [Table 3]

[0050] In the above method, α-W(110) is formed on Zn(1-100) at b / a = 0.539, and the Fddd structure is thought to be generated before α-W relaxes to the original b / a (0.71).

[0051] In the above method, the thickness of the W(110) film formed is, for example, 1 to 10 nm, preferably 2 to 9 nm, and more preferably 3 to 8 nm.

[0052] (2) A ferromagnetic layer 12 is stacked on the spin-orbit torque wiring layer 11.

[0053] Next, the ferromagnetic layer 12 is formed on the spin orbit torque wiring layer 11 by a known film formation method such as sputtering. When using sputtering, for example, one or more metals selected from the group consisting of Co, Fe, and Ni, or alloys thereof may be used as a target material.

[0054] (3) Add a voltage application mechanism

[0055] Furthermore, a mechanism for applying a voltage to the spin orbit torque wiring layer 11 is added. For example, a metal film may be formed on the spin orbit torque wiring layer 11 by evaporation or sputtering, and this metal may be used as an electrode to apply a voltage to the spin orbit torque wiring layer 11, causing a current to flow in a direction parallel to the layer. Examples of materials for the electrode include metals and ITO (Indium Tin Oxide), among which metals include Cu, Au, and Al.

[0056] [Magnetoresistive element]

[0057] A known configuration may be used for the magnetoresistive effect element using the spin current magnetization rotating element. For example, the structure of the magnetoresistive effect element taught in U.S. Patent Application Publication No. 2022 / 0,149,269 or U.S. Patent Application Publication No. 2019 / 0,267,540 may be used. The descriptions of the structures of the magnetoresistive effect elements in U.S. Patent Application Publication No. 2022 / 0,149,269 and U.S. Patent Application Publication No. 2019 / 0,267,540 are incorporated herein by reference.

[0058] 4 is a cross-sectional view showing an embodiment of a magnetoresistive effect element. A rotatable ferromagnetic layer (first ferromagnetic layer) 42, a non-magnetic layer 43, and a ferromagnetic layer (second ferromagnetic layer) 44 with a fixed magnetization direction are stacked in this order on the surface of a spin orbit torque wiring layer 11.

[0059] The magnetization of the second ferromagnetic layer is preferably substantially perpendicular to the ferromagnetic layer, but may be tilted. In this magnetoresistive element, a low resistance state is achieved when the magnetization of the first ferromagnetic layer 42 and the magnetization of the second ferromagnetic layer 44 are oriented in the same direction (parallel state), and a high resistance state is achieved when the magnetization of the first ferromagnetic layer 42 and the magnetization of the second ferromagnetic layer 44 are oriented in opposite directions (antiparallel state). In this way, the low resistance state and the high resistance state may be switched by rotating the magnetization of the magnetization-rotatable first ferromagnetic layer 42. The magnetoresistive element can function as a storage cell by using the difference in resistance value before and after switching as storage information.

[0060] That is, when a current is passed through the spin orbit torque wiring layer 41 of the magnetoresistive element in a layer-parallel direction (for example, the direction of the horizontal arrow in FIG. 2), a spin current is generated in a direction perpendicular to the current due to the spin orbit interaction (spin Hall effect), and spin accumulation polarized in a direction perpendicular, parallel, or oblique to the interface between the spin orbit torque wiring layer 41 and the first ferromagnetic layer 42 is generated. This spin accumulation applies a spin orbit torque to the magnetization of the first ferromagnetic layer 42, causing magnetization rotation in the ferromagnetic layer 42. In this way, switching between a low resistance state and a high resistance state may be performed depending on whether or not there is a current in the spin orbit torque wiring layer 41 in the layer-parallel direction.

[0061] In one embodiment, the nonmagnetic layer 43 is made of an insulator. Examples of insulator materials include ceramics containing metal oxides, and examples of metal oxides include magnesium oxide.

[0062] In one embodiment, the nonmagnetic layer 43 is a metal, such as Cu or Ru.

[0063] The magnetization direction of the second ferromagnetic layer 44 is fixed. A known method may be used to fix the magnetization direction. For example, the coercive force of the second ferromagnetic layer 44 may be greater than the coercive force of the first ferromagnetic layer 42. Furthermore, the magnetization direction of the second ferromagnetic layer 44 may be fixed by exchange coupling with an antiferromagnetic layer.

[0064] In one embodiment, the second ferromagnetic layer 44 may contain a ferromagnetic material made of one or more metals selected from the group consisting of Co, Fe, Ni, and Gd, alloys of these metals, Heusler alloys such as Cu-Mn-Al alloys and Mn-Cu-Sn alloys, or other ferromagnetic materials, similar to the first ferromagnetic layer 42. Specific examples of other ferromagnetic materials include oxides such as chromium dioxide.

[0065] The first ferromagnetic layer 42 and the second ferromagnetic layer 44 may be formed of the same material or different materials. From the viewpoint of increasing the difference between the low resistance state and the high resistance state, it is preferable that the magnetization directions of the first ferromagnetic layer 42 and the second ferromagnetic layer 44 are parallel or nearly anti-parallel. That is, when the magnetization direction of the first ferromagnetic layer 42 is substantially perpendicular to the layer direction, it is preferable that the magnetization direction of the second ferromagnetic layer 44 is also substantially perpendicular to the layer direction, and when the magnetization direction of the first ferromagnetic layer 42 is substantially parallel to the layer direction, it is preferable that the magnetization direction of the second ferromagnetic layer 44 is also substantially parallel to the layer direction.

[0066] The magnetoresistive effect element of the present disclosure can be fabricated by the following procedure: (1) creating a spin orbit torque wiring layer 41, (2) stacking a first ferromagnetic layer 42 on the spin orbit torque wiring layer 41, (3) stacking a non-magnetic layer 43 on the first ferromagnetic layer 42, (4) stacking a second ferromagnetic layer 44 on the non-magnetic layer 43, and (5) adding a voltage application mechanism.

[0067] Of these, (1) forming the spin orbit torque wiring layer 41, (2) stacking the first ferromagnetic layer 42 on the spin orbit torque wiring layer 41, and (5) adding a voltage application mechanism are the same as those described in the manufacturing method of the spin current magnetization rotating element, so their description will be omitted.

[0068] (3) Laminating the first ferromagnetic layer 42 on the nonmagnetic layer 43

[0069] The nonmagnetic layer 43 is formed on the first ferromagnetic layer 42 by a known film formation method such as sputtering. When sputtering is used, a material capable of forming a nonmagnetic layer can be used as a target material.

[0070] (4) Laminating the second ferromagnetic layer 44 on the nonmagnetic layer 43

[0071] Next, a second ferromagnetic layer 44 film is formed on the nonmagnetic layer 43 by a known film formation method such as sputtering. When sputtering is used, one or more metals selected from the group consisting of Co, Fe, Ni, and Gd, or alloys of these metals can be used as the target material, as with the first ferromagnetic layer.

[0072] In the magnetoresistive element of the present disclosure, a relatively large spin current is generated in the spin orbit torque wiring layer, and therefore the resistance can be switched by a small current.

[0073] [Magnetic memory]

[0074] The magnetic memory may be configured by using a plurality of the above-described magnetoresistive effect elements as storage cells. A known configuration may be used for a magnetic memory using a spin current magnetization rotating element. For example, the magnetic memory structure taught in U.S. Patent Application Publication No. 2022 / 0,149,269 or U.S. Patent Application Publication No. 2019 / 0,267,540 may be used. The descriptions of U.S. Patent Application Publication No. 2022 / 0,149,269 and U.S. Patent Application Publication No. 2019 / 0,267,540 regarding the magnetic memory structure are incorporated herein by reference.

[0075] 5 is a circuit diagram showing an embodiment of wiring for storage cells constituting a part of the magnetic memory of the present disclosure. A plurality of storage cells as shown in FIG. 5 are arranged in a matrix and driven.

[0076] In each storage cell, a magnetoresistive element is formed by stacking, in this order, a rotatable ferromagnetic layer (first ferromagnetic layer) 52, a non-magnetic layer 53, and a ferromagnetic layer (second ferromagnetic layer) 54 with a fixed magnetization direction on the surface of a spin-orbit torque wiring layer 51. The operation of the magnetoresistive element in the magnetic memory is the same as that described above for the magnetoresistive element.

[0077] The spin-orbit torque wiring layer 51 is provided with two power supply electrodes 56, which are connected to the sources of transistors 60, respectively. The gates of the transistors 60 are connected to a word line 58, and the drains of the two transistors 60 are connected to a first write bit line 59 and a second write bit line 59′, respectively. The second ferromagnetic layer 54 is connected to a read bit line 57 via an electrode 55.

[0078] Here, for example, data "1" is assigned to a high resistance state, and data "0" is assigned to a low resistance state. When data "1" is written to a storage cell in which data "0" has been written, the first write bit line 59 is set to an H (high voltage) level, and the second write bit line 59' is set to an L (low voltage) level. Then, by setting the word line 58 to an H level, a current flows from the first write bit line 59 to the second write bit line 59' via the spin-orbit torque wiring layer 51, the magnetization of the first ferromagnetic layer 52 is reversed, and data "1" is written.

[0079] Conversely, for example, when data "1" is written to a storage cell to which data "1" has been written, the first write bit line 59 is set to L level and the second write bit line 59' is set to H level. Then, by setting the word line 58 to H level, a current flows from the second write bit line 59' to the first write bit line 59 via the spin-orbit torque wiring layer 51, the magnetization of the first ferromagnetic layer 52 is reversed, and data "0" is written.

[0080] When reading data stored in a storage cell, either the first write bit line 59 or the second write bit line 59' is set to H level, and the other is opened. Furthermore, by setting the read bit line 57 to L level and the word line 58 to H level, a current flows from the first write bit line 59 and the second write bit line 59' to the read bit line 57. By measuring the magnitude of this current, it is determined whether the storage cell is in a high-resistance state or a low-resistance state, and the data written in the storage cell is obtained.

[0081] In one embodiment of the magnetic memory, storage cells such as those shown in FIG. 5 are arranged in a matrix, and predetermined write / read operations are performed by controlling the levels of the write bit line, read bit line, and word line using a controller.

[0082] In the magnetic memory of this embodiment, a relatively large spin current is generated in the spin-orbit torque wiring layer, so that it can be operated with a small current.

[0083] Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. [Industrial Applicability]

[0084] In the embodiment of the present disclosure, since the spin orbit torque wiring layer has a specific crystal structure, when a current is passed through the spin orbit torque wiring layer in the spin current magnetization rotor, a relatively large spin current is obtained. Therefore, when the spin current magnetization rotor is used in a magnetoresistive element or a magnetic memory, the magnetoresistive element or the magnetic memory can be driven with a smaller current. [Explanation of symbols]

[0085] 11 Spin-orbit torque wiring layer 12 Ferromagnetic layer 41 Spin-orbit torque wiring layer 42 First ferromagnetic layer 43 Non-magnetic layer 44 Second ferromagnetic layer 51 Spin-orbit torque wiring layer 52,54 ferromagnetic layer 53 Non-magnetic layer 55,56 electrode 57 Read bit line 58 word lines 59 First write bit line 59' Second write bit line 60 transistors

Claims

1. a first ferromagnetic layer having a changeable magnetization direction; a spin-orbit torque wiring layer adjacent to the first ferromagnetic layer, the spin-orbit torque wiring layer includes one or more elements, and at least one of the one or more elements has a crystalline structure; If the dimensions of the lattice constants of the crystal structure are represented by a, b, and c, then: the internal coordinates of the atoms occupying the unit cell are (0,0,0), (0.5,0.5,0), (0.25,0.75,0.25), (0.75,0.25,0.25), (0,0.5,0.5), (0.5,0,0.5), (0.75,0.75,0.75), and (0.25,0.25,0.75); The ab plane is stacked to have a four-fold spiral structure along the c axis, A spin current magnetization rotating element in which the angle (γ) between the a-axis and the b-axis is in the range of 60°≦γ≦120°, and the ratio of b to a (b / a) is in the range of 0.2≦b / a≦1.

0.

2. The spin current magnetization rotating element according to claim 1 , wherein the one or more elements contained in the spin orbit torque wiring layer are heavy metal elements having an atomic number equal to or greater than that of yttrium.

3. 3. The spin current magnetization rotating element according to claim 2, wherein the heavy metal element is tungsten.

4. 3. The spin current magnetization rotating element according to claim 2, wherein the heavy metal element is tungsten having an orthorhombic structure with a space group of Fddd.

5. 5. The spin current magnetization rotating element according to claim 1, wherein γ is in the range of 85°≦γ≦95°.

6. 6. The spin current magnetization rotating element according to claim 1, wherein b / a is in the range of 0.4≦b / a≦0.

6.

7. 7. The spin current magnetization rotating element according to claim 1, wherein b / a is in the range of 0.47≦b / a≦0.

55.

8. The spin current magnetization rotating element according to any one of claims 1 to 7, further comprising a substrate made of a semiconductor or an insulator, and the spin orbit torque wiring layer is formed directly on the substrate or via an intermediate layer.

9. The spin current magnetization rotating element according to any one of claims 1 to 8, a second ferromagnetic layer having a fixed direction of magnetization; a non-magnetic layer disposed between the first ferromagnetic layer and the second ferromagnetic layer;

10. A magnetic memory comprising a plurality of magnetoresistive effect elements according to claim 9.

Images