Buffer layers, interlayers, and barrier layers comprising housler alloy for SOT-based sensors, memories, and storage devices

Abstract

The present disclosure generally relates to spin-orbit torque (SOT) devices including bismuth antimony (BiSb) layers. The SOT device also includes a non-magnetic buffer layer, a non-magnetic interlayer, a ferromagnetic layer, and a non-magnetic barrier layer. One or more of the barrier layer, interlayer, and buffer layer includes a polycrystalline non-Heusler alloy material, or a Heusler alloy and a material selected from the group consisting of Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In. The present invention relates to a Chousler alloy which is a full Chousler alloy comprising X2YZ or a semi-Chousler alloy comprising XYZ, where X is one of Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt and Au, Y is one of Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf and W, and Z is one of B, Al, Si, Ga, Ge, As, In, Sn, Sb and Bi.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. non-provisional application No. 18 / 197,495, filed on May 15, 2023, entitled “Buffer layers, interlayers and barrier layers comprising Heusler alloys for SOT-based sensors, memories and storage devices,” and is incorporated herein by reference in its entirety for all purposes, which application claims priority to U.S. provisional patent application serial number 63 / 391,956, filed on July 25, 2022. Background Art Technical Field

[0003] Embodiments of the present disclosure are generally directed to spin-orbit torque (SOT) devices including bismuth antimony (BiSb) layers.

[0004] Description of Related Art

[0005] BiSb layers are narrow-bandgap topological insulators that exhibit both a giant spin Hall effect and high conductivity. BiSb is a material that has been proposed in various spin-orbit torque (SOT) device applications, such as spin Hall layers for magnetoresistive random access memory (MRAM) devices and energy-assisted magnetic recording (EAMR) write heads.

[0006] However, there may be several obstacles to using BiSb materials in commercial SOT applications. For example, BiSb materials have low melting points, large grain sizes, significant Sb migration issues upon thermal annealing due to their film roughness, difficulty maintaining the desired (012) or (001) orientation for maximum spin Hall effect, and are generally soft and easily damaged by ion milling.

[0007] Therefore, there is a need for an improved SOT device utilizing a BiSb layer having a desired crystal orientation and a high signal-to-noise ratio. Summary of the invention

[0008] The present disclosure as a whole relates to a spin-orbit torque (SOT) device including a bismuth antimony (BiSb) layer. The SOT device also includes a non-magnetic buffer layer, a non-magnetic interlayer, a ferromagnetic layer, and a non-magnetic barrier layer. One or more of the barrier layer, interlayer, and buffer layer include a polycrystalline non-Heusler alloy material, or a Heusler alloy and a material selected from Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, and In. The Heusler alloy is a full Heusler alloy containing X2YZ or a half Heusler alloy containing XYZ, wherein X is one of Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au, Y is one of Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, and W, and Z is one of B, Al, Si, Ga, Ge, As, In, Sn, Sb, and Bi.

[0009] In one embodiment, the SOT device includes a first nonmagnetic layer and a bismuth antimony (BiSb) layer, wherein the first nonmagnetic layer comprises a Heusler alloy and a material selected from Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B and In, and the BiSb layer is arranged in contact with the first nonmagnetic layer.

[0010] In another embodiment, a SOT device includes: a textured layer, a non-magnetic buffer layer disposed on the textured layer, a bismuth antimony (BiSb) layer above the non-magnetic buffer layer, a non-magnetic interlayer disposed on the BiSb layer, a ferromagnetic layer disposed on the non-magnetic interlayer, and a non-magnetic barrier layer disposed on the ferromagnetic layer, wherein one or more of the non-magnetic barrier layer, the non-magnetic interlayer, and the non-magnetic buffer layer comprises a polycrystalline non-Heusler alloy material, or a Heusler alloy and a material selected from Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In.

[0011] In yet another embodiment, the SOT device includes a seed layer, a textured layer disposed on the seed layer, a ferromagnetic layer disposed on the textured layer, a non-magnetic buffer layer disposed on the ferromagnetic layer, a bismuth antimony (BiSb) layer above the non-magnetic buffer layer, and a non-magnetic interlayer disposed on the BiSb layer, wherein one or more of the non-magnetic interlayer and the non-magnetic buffer layer comprises a polycrystalline non-Heusler alloy material, or a Heusler alloy and a material selected from Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B and In. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Thus, a detailed understanding of the manner in which the above-mentioned features of the present disclosure are understood, a more particular description of the present disclosure, the above brief overview, can be obtained by reference to the embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the drawings illustrate only typical embodiments of the present disclosure and are therefore not to be considered limiting of its scope, as the present disclosure may admit to other equally effective embodiments.

[0013] Figure 1 is a schematic diagram of certain embodiments of a magnetic media drive including a magnetic recording head having a SOT device.

[0014] Figure 2 is a partial cross-sectional side view of some embodiments of a read / write head having a SOT device.

[0015] FIG. 3A to FIG. 3C An MFS view of a read head including a SOT device according to various embodiments is shown.

[0016] FIG. 4A to FIG. 4B A top SOT device according to various embodiments is shown.

[0017] Figure 5 A bottom SOT device according to another embodiment is shown.

[0018] Figure 6 A graph showing the crystal orientation of a BiSb layer for various SOT devices having an interlayer and a barrier layer each including a Heusler alloy according to an embodiment is shown.

[0019] Fig. 7A is used in MAMR write heads, such as Figure 1 Schematic cross-sectional view of a SOT device for use in a magnetic recording head of a drive or other suitable magnetic media drive.

[0020] FIG. 7B to FIG. 7C Is has Fig. 7A Schematic MFS view of certain embodiments of a portion of a MAMR write head for a SOT device.

[0021] Figure 8 is a schematic cross-sectional view of a SOT used as an MRAM device.

[0022] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. DETAILED DESCRIPTION

[0023] Hereinafter, reference is made to embodiments of the present disclosure. However, it should be understood that the present disclosure is not limited to the specifically described embodiments. On the contrary, any combination of the following features and elements (whether or not related to different embodiments) is considered to realize and practice the present disclosure. In addition, although the embodiments of the present disclosure can achieve advantages that are superior to other possible solutions and / or superior to the prior art, whether a specific advantage is achieved by a given embodiment is not a limitation to the present disclosure. Therefore, the following aspects, features, embodiments and advantages are merely illustrative, and are not considered to be elements or limitations of the appended claims, unless explicitly stated in the claims. Similarly, reference to "the present disclosure" should not be interpreted as a summary of any inventive subject matter disclosed herein, and should not be considered to be elements or limitations of the appended claims, unless explicitly stated in the claims.

[0024] The present disclosure as a whole relates to a spin-orbit torque (SOT) device including a bismuth antimony (BiSb) layer. The SOT device also includes a non-magnetic buffer layer, a non-magnetic interlayer, a ferromagnetic layer, and a non-magnetic barrier layer. One or more of the barrier layer, interlayer, and buffer layer comprises a polycrystalline non-Heusler alloy material, or a Heusler alloy and a material selected from Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In. The Heusler alloy is a full Heusler alloy comprising X2YZ or a half Heusler alloy comprising XYZ, wherein X is one of Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au, Y is one of Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, and W, and Z is one of B, Al, Si, Ga, Ge, As, In, Sn, Sb, and Bi.

[0025] The BiSb layer with (012) orientation or (001) orientation has a significant spin Hall angle effect and high conductivity. Therefore, the BiSb layer with (012) orientation or (001) orientation can form a SOT device. For example, the BiSb layer with (012) orientation or (001) orientation can be used as a spin Hall layer in a spin-orbit torque device in a magnetic recording head, such as as part of a write head (MAMR). In another example, the BiSb layer with (012) orientation or (001) orientation can be used in a nano-oscillator device for a read head application that detects signals in the frequency domain. In another example, the BiSb layer with (012) orientation or (001) orientation can be used as a spin Hall electrode layer in an MRAM device. The SOT device can be a vertical stack configuration or an in-plane stack configuration. The SOT device can be used in, for example, a MAMR write head, a read head, a reader based on a nano-oscillator, MRAM, an artificial intelligence chip, and other applications.

[0026] Figure 1 1 is a schematic diagram of certain embodiments of a magnetic media drive 100 including a magnetic recording head having a SOT device. Such a magnetic media drive may be a single drive or include multiple drives. For ease of illustration, a single disk drive 100 is shown according to certain embodiments. As shown, at least one rotatable disk 112 is carried on a spindle 114 and is rotated by a drive motor 118. The magnetic recording on each disk 112 is in the form of any suitable pattern of data tracks, such as an annular pattern of concentric data tracks (not shown) on the disk 112.

[0027] At least one slider 113 is positioned near the disk 112, and each slider 113 supports one or more head assemblies 121 including SOT devices. When the disk 112 rotates, the slider 113 moves radially in and out over the disk surface 122 so that the head assembly 121 can access different tracks of the disk 112 where the desired data is written. Each slider 113 is attached to an actuator arm 119 via a suspension 115. The suspension 115 provides a slight spring force that biases the slider 113 toward the disk surface 122. Each actuator arm 119 is attached to an actuator member 127. As shown in FIG. Figure 2 The actuator device 127 shown may be a voice coil motor (VCM). A VCM comprises a coil that can move within a fixed magnetic field, the direction and speed of the coil movement being controlled by a motor current signal supplied by the control unit 129.

[0028] During operation of the disk drive 100, the rotation of the disk 112 creates an air bearing between the slider 113 and the disk surface 122, which exerts an upward force or lift on the slider 113. Thus, during normal operation, the air bearing counteracts the slight spring force of the suspension 115 and supports the slider 113 off and slightly above the disk surface 122 by a small, substantially constant spacing.

[0029] The various components of the disk drive 100 are controlled in operation by control signals (such as access control signals and internal clock signals) generated by a control unit 129. Typically, the control unit 129 includes logic control circuits, memory devices, and a microprocessor. The control unit 129 generates control signals that control various system operations, such as drive motor control signals on line 123 and head position and seek control signals on line 128. The control signals on line 128 provide the desired current distribution to optimally move and position the slider 113 to the desired data track on the disk 112. Write and read signals are transmitted to and from the write and read heads on the assembly 121 through the recording channel 125.

[0030] The above description of a typical magnetic media drive and Figure 1The accompanying drawings are for illustrative purposes only. It should be apparent that the magnetic media drive may include a large number of media or disks and actuators, and each actuator may support multiple sliders. It should be understood that the embodiments discussed herein are applicable to data storage devices such as hard disk drives (HDDs) and tape drives such as those that comply with the LTO (Linear Tape Open) standard. Therefore, unless expressly claimed, any reference to an HDD or a tape drive in the specific embodiments is only for illustrative purposes and is not intended to limit the present disclosure. For example, references to disk media in HDD embodiments are provided as examples only, and may be replaced with tape media in tape drive embodiments. In addition, references to or claims involving magnetic recording devices or data storage devices are intended to include at least both HDDs and tape drives, unless HDD or tape drive devices are expressly claimed.

[0031] Figure 2 2 is a partial cross-sectional side view of some embodiments of a read / write head 200 having a SOT device. It should be noted that although the SOT device is shown in both the read head and the write head, this is for illustrative purposes only, and in various embodiments the SOT device may be independently integrated into only the read head or only the write head, or integrated into both the read head and the write head. The read / write head 200 faces the magnetic medium 112. The read / write head 200 may correspond to Figure 1 The read / write head 200 includes a medium facing surface (MFS) 212 (such as a gas bearing surface) facing the magnetic disk 112, a write head 210, and a magnetic read head 211. Figure 2 As shown, the magnetic medium 112 moves past the write head 210 in the direction indicated by arrow 232 , and the read / write head 200 moves in the direction indicated by arrow 234 .

[0032] In some embodiments, the magnetic read head 211 is a SOT read head that includes a SOT sensing element 204 located between SOT shields S1 and S2. The magnetic field of adjacent magnetized regions in the disk 112 can be detected as a recorded bit by the SOT sensing element 204. In the SOT sensing element 204 including a BiSb layer, such as Figure 4A 4F , the current flows perpendicular to the film plane, and the signal is read out by measuring the voltage generated by the reverse spin Hall effect in the BiSb layer. The SOT devices of various embodiments may be incorporated into a read head 211 .

[0033] The write head 210 includes a main pole 220, a front shield 206, a rear shield 240, and a coil 218 for exciting the main pole 220. The coil 218 may have a "pancake" structure instead of Figure 2The "helical" structure shown is a "pancake" structure that is wrapped around the back contact between the main pole 220 and the trailing shield 240. In one embodiment, the write head 210 is a perpendicular magnetic recording (PMR) write head. In other embodiments, the write head 210 can use energy-assisted magnetic recording (EAMR) technology, such as microwave-assisted magnetic recording (MAMR) and heat-assisted magnetic recording (HAMR).

[0034] exist Figure 2 In one embodiment, a spin-orbit torque (SOT) device 250 is shown as part of a write head structure to achieve a MAMR recording effect. Figure 2 2 shows a SOT device for both the read head and the write head, but it is not required to implement the SOT device in both. The SOT device 250 is formed in the gap 254 between the main pole 220 and the tail shield 240. The main pole 220 includes a tail cone 242 and a front cone 244. The tail cone 242 extends from a position recessed in the MFS 212 to the MFS 212. The front cone 244 extends from a position recessed in the MFS 212 to the MFS 212. The tail cone 242 and the front cone 244 may have the same taper, and the taper is measured relative to the longitudinal axis 260 of the main pole 220. In some embodiments, the main pole 220 does not include the tail cone 242 and the front cone 244. Instead, the main pole 220 includes a tail side (not shown) and a front side (not shown), and the tail side and the front side are substantially parallel. The main pole 220 can be a magnetic material, such as a FeCo alloy. The front shield 206 and the tail shield 240 can be magnetic materials, such as NiFe alloys. In some embodiments, the tail shield 240 can include a tail shield thermal seed layer 241. The tail shield thermal seed layer 241 can include a high-torque sputtering material, such as CoFe, CoFeNi, or FeXN, where X includes at least one of Rh, Al, Ta, Zr, Co, and Ti. In some embodiments, the tail shield 240 does not include a tail shield thermal seed layer.

[0035] In some embodiments, the read head 211 is a spin torque oscillator (STO) read head having an STO oscillator sensing element 204 located between shields S1 and S2. The magnetic field of adjacent magnetized regions in the disk 112 can be detected as a recorded bit by the STO sensing element 204. The STO sensing element 204 includes a BiSb layer, such as Figure 4A To the SOT device of FIG. 4F . The STO reader can operate in a 2-terminal or 3-terminal configuration, where an in-plane current flows inside the SOT structure while a small sense current flows perpendicular to the film plane, and the signal is read out by measuring the frequency of the precession of the magnetic layer. The SOT device of various embodiments can be incorporated into the read head 211 .

[0036] FIG. 3A to FIG. 3C MFS views of read heads 300, 350, 375 including SOT device 301 are shown, respectively, according to various embodiments. The read heads 300, 350, 375 may be Figure 2 The SOT device 301 of each read head 300, 350, 375 can be FIG. 4A to FIG. 5 Each of the read heads 300, 350, 375 includes a SOT device 301 having dual free layers 307a, 307b.

[0037] Figure 3A The read head 300 includes a first shield 302a, a first insulating layer 313a disposed on the first shield 302a, a first spin Hall effect layer (SHL) 310a disposed on the insulating layer 313a, a first free layer (FL) 307a disposed on the first SHL 310a, a gap layer 317 disposed on the first FL 307a, a second FL 307b disposed on the gap layer 317, a second SHL 310b disposed on the second FL 307b, a second insulating layer 313b disposed on the second SHL 310b, and a second shield 302b disposed on the second insulating layer 313b. The first SHL 310a and the second SHL 310b may each individually contain bismuth antimony (BiSb). The first FL 307a and the second FL 307b may each individually contain CoFeB, Co, CoFe, or NiFe. The first shield 302a and the second shield 302b may each individually contain a magnetic material, such as NiFe. The first insulating layer 313a and the second insulating layer 313b may each include an insulating material (eg, SiN) or an oxide (eg, MgO) and may be formed with a Heusler alloy layer (hereinafter referred to as FIG. 4A to FIG. 5 ) are used in combination to maintain the texture and control the interdiffusion of Bi and Sb.

[0038] The side shield 319 is disposed adjacent to the SOT device 301 in the x-direction. The side shield 319 may include a magnetic material, such as NiFe. The third insulating layer 309 is disposed on the first SHL 310a and between the SOT device 301 and the side shield 319. The second SHL 310b is disposed in contact with the side shield 319. The antiferromagnetic cover layer 323 is disposed between the side shield 319 and the second insulating layer 313b. The first shield 302a and the second shield 302b, the first SHL 310a, and the Heusler alloy layer (hereinafter referred to as FIG. 4A to FIG. 5The first insulating layer 313a and the second insulating layer 313b used in combination to control texture and interdiffusion (as discussed in the foregoing) may each individually have a greater length in the x-direction than the first FL 307a and the second FL 307b, the gap layer 317, and the second SHL 310b. The first current 321a flows from the first shield 302a into the gap layer 317, and the second current 321b flows from the gap layer 317 into the second shield 302b. A voltage may be applied to the first SHL 310a and the second SHL 310b.

[0039] Figure 3B The read head 350 is similar to Figure 3A However, the read head 350 does not include an insulating layer or a shield. In the read head 350, the first FL 307a is disposed on the first SHL 310a and includes the following FIG. 4A to FIG. 5 The interlayer of the Heusler alloy discussed in the above may be used in combination with a non-magnetic barrier between the FL 307a and the SHL layer 310a to reduce BiSb migration. The gap layer 317 is disposed on the first FL 307a, the second FL 307b is disposed on the gap layer 317, and the second SHL 310b is disposed on the second FL 307b, and a Heusler alloy (hereinafter referred to as the SHL layer) in combination with a non-magnetic barrier layer may be used. FIG. 4A to FIG. 5 317 ) to control the (012) crystal orientation growth of the SHL 310b. The first SHL 310a and the second SHL 310b may have a greater width in the x-direction than the first FL 307a and the second FL 307b and the gap layer 317. The first current 321a flows from the first SHL 310a into the gap layer 317, and the second current 321b flows from the gap layer 317 into the second SHL 310b. Voltage may be applied to the first SHL 310a and the second SHL 310b.

[0040] Figure 3C The read head 375 is similar to Figure 3Ahowever, the read head 375 also includes seed layers 325, 329 and interlayers 327a, 327b. The read head 375 includes a first shield 302a, a first insulating layer 313a disposed on the first shield 302a, a first seed layer 325 disposed on the insulating layer 313a, a first SHL 310a disposed on the first seed layer 325, a first interlayer 327a disposed on the first SHL 310a, a first FL 307a disposed on the first interlayer 327a, a gap layer 311 disposed on the first FL 307a, a second seed layer 329 disposed on the gap layer 311, a second FL 307b disposed on the second seed layer 329, a second interlayer 327b disposed on the second FL 307b, a second SHL 310b disposed on the second interlayer 327b, a cap layer 323 disposed on the second SHL 310b, a second insulating layer 313b disposed on the second cap layer 323, and a second shield 302b disposed on the second insulating layer 313b. The cover layer 323 may include a migration barrier, such as a Heusler alloy layer (hereinafter FIG. 4A to FIG. 5 ), the migration barrier is optionally combined with an additional non-magnetic migration barrier adjacent to BiSb to control Bi, Sb migration. In one embodiment, each layer of the read head 375 has the same length in the x-direction, but in other embodiments they may vary.

[0041] The capping layer 323 comprises a material selected from the group consisting of SiN, TiN, Al2O3, SiO2, NiFeTa, NiTa, NiW, NiFeW, CoHf, CoFeHf, Pt, Co, Cu, Ni, NiCu, CoCu, Ru, Ta, Cr, Au, Rh, other non-magnetic materials, and combinations thereof. The first seed layer 325 comprises a silicide or GeNiFe layer optionally in combination with another non-magnetic barrier. The second seed layer 329 may comprise a GeNiFe layer optionally in combination with another non-magnetic barrier. The first interlayer 327a and the second interlayer 327b may each individually comprise a non-magnetic Si or Ge transition metal alloy layer (such as a NiFeGe or CoFeGe layer), a Heusler alloy layer, or other alloy, in combination with a material selected from the group consisting of Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, and In or in combination with another non-magnetic barrier to control BiSb intermixing and maintain BiSb texture.

[0042] Although FIG. 3A to FIG. 3C Each dual ferromagnetic or dual free layer SOT device 301 is shown separately, but FIG. 3A to FIG. 3CThe read heads 300, 350, 375 may alternatively utilize a single ferromagnetic or single free layer SOT device or a single ferromagnetic or single free layer SOT device including an antiferromagnetic (AFM) layer, wherein the AFM layer may include a single or multiple layers of PtMn, NiMn, IrMn, IrMnCr, CrMnPt, FeMn, other antiferromagnetic materials, or combinations thereof. An exemplary single ferromagnetic or single free layer SOT device may include a substrate or shield, a buffer layer disposed on the substrate, a free layer disposed on the buffer layer, an interlayer disposed on the free layer, a SHL disposed on the interlayer, and a capping layer disposed on the SHL. An exemplary single ferromagnetic or single free layer SOT device including an AFM layer may include an AFM layer disposed adjacent to the single ferromagnetic or single free layer SOT device, wherein the AFM layer is recessed from the MFS. Additionally, the described single or dual free layer based SOT devices may be used in magnetic sensor applications other than read sensors / readers in magnetic recording, and such sensors may be similarly fabricated into the various reader stacks shown or described.

[0043] FIG. 4A to FIG. 4B A top spin-orbit torque (SOT) device 400 , 450 is shown according to various embodiments. Figure 5 A bottom SOT device 500 is shown according to another embodiment. Each of the SOT devices 400, 450, 500 may include FIG. 4A to FIG. 5 The SOT devices 400, 450, 500 can each be used individually Figure 1 The magnetic recording head of the drive 100 or other suitable magnetic media drive, such as Figure 2 The read head 211 and / or the write head 210, and FIG. 3A to FIG. 3C One or more of the read heads 300, 350, 375. For example, Figure 3C The first seed layer 325 and the second seed layer 329 and the first interlayer 327a and the second interlayer 327b may be the buffer layer 416 and / or the interlayer 412 discussed below. FIG. 4A to FIG. 5 Various SOT devices / stacks can be used for magnetic sensors and as MRAM (such as Figure 8 A portion of the memory structure in the example shown in ).

[0044] In addition, although the SOT devices 400, 450, 500 are referred to as SOT devices, the SOT devices 400, 450, 500 can each be used individually as a spin torque oscillator (STO) device. Aspects of each SOT device 400, 450, 500 can be used in combination with each other. When the SOT device 400, 450, 500 is used in a write head, current flows in a plane to the SOT layer or bismuth antimony (BiSb) layer 410, and the ferromagnetic (FM) or free layer oscillates through the SOT generated by the spin Hall effect in the BiSb layer 410.

[0045] Figure 4A The SOT device 400 includes a first electrode 402a, a seed layer 404 disposed on the first electrode 402a, a buffer layer 406 disposed on the seed layer 404, an optional nucleation layer 408 disposed on the buffer layer 406, a BiSb layer 410 disposed on the optional nucleation layer 408 (or the buffer layer 406), an interlayer 412 disposed on the BiSb layer 410, an FM layer 414 disposed on the interlayer 412, a barrier layer 416 disposed on the FM layer 414, a capping layer 418 disposed on the barrier layer 416, and a second electrode 402b disposed on the capping layer 418. Although shown, the first electrode 402a and the second electrode 402b are optional.

[0046] Figure 4B The SOT device 450 is similar to Figure 4A SOT device 400; however, SOT device 450 also includes a texture layer 452 disposed between the seed layer 404 and the buffer layer 406, and the interlayer 412 is a multilayer structure including a first interlayer 454 disposed on the BiSb layer 410 and a second interlayer 456 disposed on the first interlayer 454. Therefore, SOT device 450 includes a seed layer 404, a texture layer 452 disposed on the seed layer 404, a buffer layer 406 disposed on the texture layer 452, an optional nucleation layer 408 disposed on the buffer layer 406, a BiSb layer 410 disposed on the optional nucleation layer 408 or the buffer layer 406, a first interlayer 454 disposed on the BiSb layer 410, a second interlayer 456 disposed on the first interlayer 454, an FM layer 414 disposed on the second interlayer 456, a barrier layer 416 disposed on the FM layer 414, and a capping layer 418 disposed on the barrier layer 416. Although Figure 4B Although not shown, the SOT device 450 may include a first electrode 402a and a second electrode 402b.

[0047] Figure 5 The SOT device 500 is similar to FIG. 4A to FIG. 4B however, the FM layer 414 is disposed below the BiSb layer 410 . Figure 5The SOT device 500 includes a seed layer 404, a texture layer 452 disposed on the seed layer 404, an FM layer 414 disposed on the texture layer 452, a buffer layer 406 disposed on the FM layer 414, a BiSb layer 410 disposed on the buffer layer 406, an interlayer 412 disposed on the BiSb layer 410, and a capping layer 418 disposed on the interlayer 412. Figure 5 Although not shown, the SOT device 500 may include the first electrode 402 a and the second electrode 402 b and / or the nucleation layer 408 .

[0048] In the SOT devices 400, 450, 500, the BiSb layer 410 may be FIG. 3A to FIG. 3C The BiSb layer 410 may have a thickness of about 100 mm in the y direction. to about The BiSb layer 410 may be referred to herein as a spin Hall effect (SHE) layer, a spin orbit torque (SOT) layer, or a topological insulator. The BiSb layer 410 may include undoped BiSb or doped BiSbX, wherein the dopant is less than about 10%, and wherein X is extracted from an element that does not readily interact with Bi or Sb, such as Cu, Ag, Ge, Mn, Ni, Co Mo, W, Sn, B, In, or an alloy combination of one or more of the foregoing elements, such as CuAg, CuNi, CoCu, AgSn. The BiSb layer 410 may have a (012) crystal orientation or a (001) crystal orientation.

[0049] In embodiments where the SOT device 400, 450, 500 includes a first electrode 402a and a second electrode 402b, the first electrode 402a and the second electrode 402b may each individually include a non-magnetic low-resistivity metal. For example, the first electrode 402a and the second electrode 402b may each include Ru, CuAg, Ta(α), W(α), Mo, Cu, Ag, Rh, Pt, etc. If the first electrode 402a and the second electrode 402b are far enough away so as not to interfere with the FM / SOT interaction, a magnetic material with low to medium resistivity may be used. The thickness of each of the first electrode 402a and the second electrode 402b in the y direction is greater than or equal to about

[0050] The capping layer 418 may include non-magnetic high-resistivity materials such as: thin ceramic oxides or nitrides of TiN, SiN and MgO; amorphous / nanocrystalline metals such as NiFeTa, NiTa, NiHf, NiFeHf, CoHf, CoFeHf, NiWTa, NiFeW, NiW, WRe, β-Ta and β-W; or nitrides, oxides or borides of the above elements, compounds and / or alloys such as NiTaN, NiFeTaN, NiWTaN, NiWN, WReN, TaN, WN, TaOx, WOx, WB, HfB, NiHfB, NiFeHfB, CoHfB and CoFeHfB, where x is a number. In some embodiments, lower atomic number (Z) materials are preferred in capping layer 418 to reduce sputtering intermixing with FM layer 414, but high Z alloys may be used if used in combination with an underlying migration barrier, or if high Z elements are used with high resistance oxides, nitrides, or borides. Capping layer 418 may include a multilayer combination of the above materials, and the overall thickness of capping layer 418 in the y direction is less than or equal to about (Nominal approx. to about ). In addition, if the bottom portion of the barrier layer 416 or the capping layer 418 has a high resistivity and is thick enough to reduce FM shunting, a lower resistivity metal may be used in the capping layer 418.

[0051] The FM layer 414 has a thickness of about to about The thickness may be , and may include NiFe, CoFe, NiFeX, CoFeX, FeX, or NiX, where X = Co, Ni, Cu, Si, Al, Mn, Ge, Ta, Hf, and B. The FM layer 414 may include any magnetic layer combination or alloy combination of these elements that may produce a low coercive, negative magnetostrictive FM layer 414, or a multilayer combination with other higher polarization materials such as Heusler alloys or high Ni-containing alloy FM layers.

[0052] The seed layer 404 may include the same material as the cap layer 418, and the seed layer 404 may be multilayered. For example, the seed layer 404 may include: non-magnetic high resistivity materials, such as thin ceramics of TiN, SiN, MgO, and Al2O3; amorphous / nanocrystalline metals, such as NiFeTa, NiTa, NiHf, NiFeHf, CoHf, CoFeHf, NiWTa, NiFeW, NiW, WRe, β-Ta, and β-W; or nitrides, oxides, or borides of the above elements, compounds, and / or alloys, such as NiTaN, NiFeTaN, NiWTaN, NiWN, WReN, TaN, WN, TaOx, WOx, WB, HfB, NiHfB, NiFeHfB, CoHfB, and CoFeHfB, where x is a number. Since the seed layer 404 is below or under the FM layer 414 in each SOT device 400, 450, 500, the high Z amorphous alloys in the seed layer 404 do not detrimentally affect SOT intermixing as they do in the cap layer 418. The thickness of the seed layer 404 in the y direction is less than or equal to about (Nominal approx. to about ). If magnetic electrodes are used in the device stack, the seed layer 404 and the capping layer 418 may each be individually thicker.

[0053] The texture layer 452 may include RuAl (wherein Ru is between about 45% and about 55%), CrMo (wherein Mo is between about 25% and about 50%), or a multilayer CrMoX with CrX (wherein X=Ti, Ru, Mo, or W). The texture layer 452 has a (001) texture. The texture layer 452 may have a B2 or BCC crystal structure, where the a-axis lattice parameter is about to about The texture layer 452 has a thickness of about to about Thickness.

[0054] Each of the buffer layer 406, the interlayer 412, the barrier layer 416, and the nucleation layer 408 comprises a magnetic or non-magnetic Heusler alloy, wherein the Heusler alloy may be a full Heusler alloy (i.e., X2YZ) or a half Heusler alloy (i.e., XYZ). Full X2YZ-type Heusler alloys generally have an L21, cF16, or C1b-type structure, wherein the a-axis is about Peace This is a perfect match for the RuAl or CrMo texture layer 452. Semi-XYZ Heusler alloys generally have a B2-type or Pm-3m-type structure, where the a-axis is about to about However, the type or structure may vary with respect to half-Heusler alloys and full-Heusler alloys. For example, RuMnAl, RhMnAl and Al2CuRh have a Pm-3m structure, and Ni2MnAl and Mn2NiAl have a cF16 structure, while Al2NiMn has a B2 structure.

[0055] For full and half Heusler alloys, X can be one of Li, Mg, Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Cd, Ir, Pt, or Au; Y can be one of Li, Be, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, or W; and Z can be one of B, Mg, Al, Si, Zn, Ga, Ge, As, In, Sn, Sb, Pb, or Bi. Some examples of nonmagnetic Heusler alloys include Ti2MnAl, Fe2VAl Cr2CoAl CoT3S Mn2VSi、V2VAl [Mn 1-x Co x ]2VAl(x=0.5) [Mn 1-x Co x ]2VSi(x=0.25) and CoMnNbAl, CoZrFeAl. Examples of magnetic Heusler alloys with large spin polarization include Co2MnSb Co2MnGe CoMnSb NiMnSb, Co 2 FeGe, Co 2 MnSn, and Co 2 MnFeGe, each of which is not easily mixed with the BiSb layer 410 .

[0056] In addition, each of the buffer layer 406, the interlayer 412, the barrier layer 416 and the nucleation layer 408 includes: (1) an amorphous / nanocrystalline layer formed by a combination of a Heusler alloy and an element, or an alloy layer that is not easily mixed with the SOT or FM layer, or a uniform alloy formed by co-sputtering a Heusler alloy with other elements, or an alloy that is not easily mixed with the SOT or FM layer, or (2) a polycrystalline Heusler alloy that is an epitaxial layer in the SOT device 400, 450, 500. With respect to the amorphous / nanocrystalline buffer layer 406, the nucleation layer 408, the interlayer 412, and the barrier layer 416, thin polycrystalline Heusler alloys (magnetic and non-magnetic, and full or half Heusler alloys) may be used when alloyed with other elements that do not readily mix with the BiSb layer 410, such as Cu, Ag, Ge, Mn, Ni, Co Mo, W, Sn, B, and In, or alloy combinations of one or more of the foregoing elements (such as CuAg, CuNi, CoCu, AgSn). The nucleation layer 408 may also be a very thin (e.g., dusting) layer of these foregoing elements or very thin alloy combinations of these elements (such as CuAg, CuNi, CoCu, and AgSn).

[0057] The nonmagnetic amorphous / nanocrystalline buffer layer 406 and the nucleation layer 408 are effectively formed using an amorphous or nanocrystalline layer formed from a Heusler alloy alloyed with other elements that are not miscible with the BiSb layer 410 in the following situations: (1) after deposition and room temperature (RT) intermixing; (2) post-annealing before deposition of the BiSb layer 410; (3) in a single uniform composition layer, depositing the nonmagnetic amorphous / nanocrystalline alloy using a single alloy target; or (4) co-sputtering with a target containing an element of the Heusler alloy and a multi-element combination of the above elements that are not miscible.

[0058] The interlayer 412 and barrier layer 416 are formed in a similar manner to the buffer layer 406 and nucleation layer 408 (although the nucleation layer 408 may also be simply the aforementioned elements or any non-magnetic alloy combination of these elements); however, after deposition and RT intermixing, the resulting graded interlayer 412 or barrier layer 416 does not have to be amorphous, as long as the resulting layer has high electrical resistance and reduces intermixing of the interlayer 412 / barrier layer 416 with the BiSb layer 410 or with the FM layer 414.

[0059] Regarding polycrystalline Heusler alloys, thin layers of Heusler alloys, both magnetic and non-magnetic, full or half Heusler alloys, can be used as buffer layers 406, interlayers 412, barrier layers 416, and / or nucleation layers 408 in (100) textured layer SOT devices (in which case the SOT orientation is (012)). Heusler alloys typically have higher resistivity than FM layer 414 and transport spin current or generate high spin polarization while providing and maintaining (100) growth. Heusler alloys also have excellent lattice matching capabilities with MgO tunnel barrier layers and bcc FM alloys. A (100) textured layer, such as textured layer 452, can be used to establish a (100) texture, and a non-magnetic Heusler X2YZ or XYZ with a cF16 (C1b, L21) or B2 structure can be used to transfer texture to a BiSb layer 410, which in turn grows a strong (012) texture for the BiSb layer 410 with an epitaxial bcc, B2 or C1b, cF16, L21 Heusler interlayer to produce a strong epitaxial (100) texture for a bcc or B2 FM layer 414.

[0060] Other non-Heusler, non-magnetic materials that can be used for one or more of the epitaxially grown epitaxial buffer layer 406, interlayer 412 and / or barrier layer 416 are: B2 or bcc materials such as NiAl, RuAl, RhAl, Mn3Al, V, Mo, W, TiW, CrX, where x = Ti, Ru, Mo or W; CrMo (where Mo is between about 20% and about 50%), CrMoTi, Cr, MoV, CrMoW; or CrXY, where X and Y are each individually selected from: Al, Ti, Mn, Co, Ni, Ru, Mo, Rh, W and V.

[0061] In some embodiments, the barrier layer 416 may be formed of a thin ceramic oxide or nitride layer such as TiN, WN, SiN, and Al2O3, and MgO may be used as the barrier layer 416 or combined with other high resistance non-magnetic material layers. The top portion of the multilayer barrier layer 416 (not in direct contact with the FM layer 414) may also include a high resistivity heavy metal amorphous or amorphous / nanocrystalline metal such as NiFeTa, NiTa, NiHf, NiFeHf, CoHf, CoFeHf, NiWTa, NiFeW, NiW, and WRe; nanocrystalline metals such as β-Ta and β-W; or nitrides, oxides, or borides of the foregoing elements or alloys such as NiTaN, NiFeTaN, NiWTaN, NiWN, WReN, TaN, WN, TaOx, WOx, TaBx, WBx, HfBx, NiHfB, NiFeHfB, and CoHfB, where x is a number. When combined with the aforementioned non-interacting elements or alloy combinations of these elements, the bottom portion of the barrier layer 416 can be an amorphous / nanocrystalline material formed of a Heusler alloy or other magnetic alloy material. Higher resistivity non-magnetic alloys that do not interact with the FM layer 414, such as CuAg, CuNi, NiAg, CoCu, NiAl, RuAl, RhAl, and AgSn can also be used as the barrier layer 416. The barrier layer 416 may also be a polycrystalline non-magnetic Heusler alloy or semi-Heusler alloy, or other B2 or bcc materials, such as NiAl, RuAl, RhAl, Mn3Al, V, Mo, W, TiW, and CrX, where x = Ti, Ru, Mo, or W; CrMo (where Mo is between about 20% and about 50%), CrMoTi, Cr, MoV, CrMoW; or CrXY, where X and Y are each individually selected from: Al, Ti, Mn, Co, Ni, Ru, Mo, Rh, W, and V; or any combination of these material layers with a non-interacting layer of higher resistance adjacent to the FM layer, etc.

[0062] Examples of high resistance amorphous barrier layer 416 materials include Ge / CoFe / CuAg (as used herein, " / " represents a separate sublayer in a stack or layer) when alloyed with a non-magnetic material that is not easily intermixed with FM layer 414 (where Ge / CoFe can form a single layer or can be deposited as an alloy layer at room temperature, and where Ge has a relative humidity of about 10%. The thickness of CoFe is about The thickness of CuAg is about ), CuAg / Ge / CoFe / CuAg (wherein CuAg / Ge / CoFe can form a single layer or can be deposited as an alloy layer at room temperature, and wherein CuGe has a thickness of about The thickness of Ge is about The thickness of CoFe is about The thickness of CuAg is about % Ge) or a thin non-magnetic alloy layer such as CoFeGe, NiFeGe, CoFeGeAg, etc. (the alloy composition for alloying with Ge should be greater than about 44at.% Ge to make the alloy non-magnetic). Additional examples of elements, compounds, or crystalline / amorphous / nanocrystalline materials that can be used as barrier layers when alloyed with non-magnetic materials that are not easily blended with the FM layer 414 include: Ge / CoFe / NiFeTaN (where Ge / CoFe can form a single layer at room temperature or can be deposited as an alloy layer, and where Ge has about The thickness of CoFe is about The thickness of NiFeTaN is about Ge / CoFe / MgO (where Ge / CoFe can form a single layer at room temperature or can be deposited as an alloy layer, and where Ge has a thickness of about The thickness of CoFe is about The thickness of MgO is about and MgO / Ge / CoFe (wherein Ge / CoFe can form a single layer at room temperature or can be deposited as an alloy layer, and wherein MgO has a thickness of about The thickness of Ge is about The thickness of CoFe is about An example of a barrier layer 416 or interlayer 412 using an alloy having an X2YZ Heusler alloy would be Ge / Co2FeGe (which can be formed as a single layer at room temperature or can be deposited as an alloy layer, and wherein Ge is about Thick and Co2FeGe is about or using an alloy having an XYZ half-Heusler alloy such as Ge / CoFeGe (which can form a single layer at room temperature or can be deposited as an alloy layer, wherein Ge is about Thick and CoFeGe is about thick); and Ge / CoA (which can form a single layer at room temperature or can be deposited as an alloy layer), Ge / FeA (which can form a single layer at room temperature or can be deposited as an alloy layer), or Ge / NiA (which can form a single layer at room temperature or can be deposited as an alloy layer), wherein A can be one or more elements belonging to a full Heusler alloy X2YZ or a half Heusler alloy XYZ; or a very thin (i.e., about 1000 μm) alloy with CuAg, NiCr, CoCu, AgSn, etc. to about A non-magnetic seed layer or cap layer (thick dust layer) is used in combination, such as Ge / X2YZ / CuAg, Ge / X2YZ / CuNi, CuNi / Ge / X2YZ or CuAg / Ge / X2YZ / CuNi. The alloy composition should be non-magnetic, such as an alloy with one of the aforementioned non-interacting elements or an alloy of these elements (such as Ge), wherein Ge exceeds about 44at.% to make the alloy non-magnetic.

[0063] The barrier layer 416 may include a multi-layer stack, wherein the multi-layer stack includes one or more of the above-mentioned elements, compounds, or crystalline / amorphous / nanocrystalline metals. The thickness of the barrier layer 416 in the y direction may be about to about This depends on the resistivity of the barrier layer 416 and the effectiveness of the barrier layer 416 in reducing FM intermixing and FM shunting in the SOT devices 400 , 450 , 500 .

[0064] The interlayer 412 may include any of the aforementioned elements, compounds, or crystalline / amorphous / nanocrystalline metals that the barrier layer 416 may include. In addition, the interlayer 412 may include a non-magnetic alloy or multilayer stack containing one or more of the following elements Cu, Ag, Ge, Mn, Ni, Co, Mo, W, In, B, and Sn; or a combination with a magnetic alloy such as CoA, FeA, and NiA, where A may be one or more elements belonging to a full Heusler alloy X2YZ or a half Heusler alloy XYZ, where X is selected from the group consisting of: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au; where Y is selected from the group consisting of: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, and W; where Z is selected from the group consisting of: B, Al, Si, Ga, Ge, As, In, Sn, Sb, and Bi. The magnetic alloy or Heusler alloy should be combined with other layers, combinations of elements or other alloys to form a non-magnetic layer or multi-layer stack after deposition and intermixing at room temperature, or deposited as a non-magnetic single layer alloy, or a combination thereof. The overall total thickness of the interlayer 412 is less than about Such as to about To ensure sufficient magnetic coupling of the FM layer 414 to the BiSb layer 410. Nonmagnetic polycrystalline Heusler alloys can also be used for the interlayer 412, such as V2VAl or [Mn 0.5 Co 0.5 ]2VA1 etc.

[0065] The interlayer 412 should have a higher resistivity and be non-magnetic. Thin, high resistivity, low Z ceramic oxide and nitride layers (thin layers) of TiN, SiN, Al2O3, MgO can be used for the interlayer 412. In addition, if not disposed in direct contact with the BiSb layer 410, other materials that can be used as the interlayer 412 include: high resistivity heavy metal amorphous / nanocrystalline metals such as NiFeTa, NiTa, NiWTa, NiFeW, NiW, WRe, etc.; nanocrystalline metals such as β-Ta or β-W; or nitrides, oxides or borides of the aforementioned elements or alloys such as NiTaN, NiFeTaN, NiWTaN, NiWN, WReN, TaN, WN, TaOx, WOx, TaBx, WBx and HfBx. Higher resistivity non-magnetic alloys that do not readily interact with the BiSb layer 410 or the FM layer 414 may also be used for the interlayer 412, such as Cu, Ag, Ge, Mn, Ni, Co Mo, W, Sn, B, In, and multi-element alloy combinations thereof, such as CuAg, CuNi, NiAg, CoCu, NiAl, RuAl, RhAl, CuCo, and AgSn.

[0066] Examples of high resistance amorphous materials for interlayer 412 include Ge / CoFe / CuAg (which can form a single layer at room temperature or can be deposited as an alloy layer), CuAg / Ge / CoFe / CuAg (which may form a single layer at room temperature or may be deposited as an alloy layer), or a single alloy non-magnetic layer of CoFeGe, NiFeGe, CoFeGeAg, etc. The interlayer 412 may include a thin multilayer stack composed of the aforementioned elements, compounds, or crystalline / amorphous / nanocrystalline layers, as long as the entire multilayer stack is non-magnetic and has high resistivity.

[0067] Magnetic alloys and magnetic Heusler alloys can be used if used in combination with other elements or alloys as described above, such that when deposited, the materials intermix at room temperature or after post-annealing to form a non-magnetic stack. Examples include layers of NiFeX, CoFeX, NiX, FeX, CoX, where X is an element that does not interact readily with BiSb, such as Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In, or magnetic Heusler alloys deposited on a non-interacting element or alloy layer (such as a Ge layer) and in a single alloy deposited layer, where the resulting Ge content in the intermixed alloy makes it non-magnetic (e.g., in the case of alloying with Ge, the Ge content should be greater than or equal to about 44 at.%); or combined with sufficiently thick layers of elements that do not interact readily with BiSb (such as Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In) to form their multi-element, non-magnetic, high resistivity combination; or a single polycrystalline non-magnetic Heusler layer.

[0068] Another example of a material that can be used for the interlayer 412 includes: Ge / CoFe / NiFeTaN (where Ge / CoFe can form a single layer or can be deposited as an alloy layer at room temperature, and where Ge has a relative humidity of about 10%. The thickness of CoFe is about The thickness of NiFeTaN is about thickness).

[0069] In addition, when used in alloy combinations with Ge to form graded nonmagnetic layers, such as NiFeGe, CoFeGe, CoCu, NiCu and CuAg alloys, or Heusler alloy combinations mixed with Ge, wherein the Ge content is about greater than or equal to about 44 atomic percent (at.%), materials similar to interlayer 412 can be used in barrier layer 416, as long as these materials are not easily mixed with FM layer 414, such as Cu, Ag, Ge, Mn, Ni, Co Mo, W, Sn, B, In and alloy combinations thereof. The Ge content of about greater than or equal to about 44 at.% ensures that even magnetic Heusler alloys are nonmagnetic when intermixed with Ge or deposited as a single alloy with Ge>44% or in combination with other non-mixing elements (i.e., Cu, Ag, Mn, Mo, Ni, W, In, B and Sn), so that the final thin multilayer interlayer 412 and / or barrier layer 416 is nonmagnetic after deposition mixing or post annealing.

[0070] exist Figure 4BIn the STO device 450, the first interlayer 454 may include any of the non-magnetic materials listed above, such as a polycrystalline non-magnetic Heusler alloy or a high resistivity fcc oxide layer (such as a thin MgO tunnel barrier). The second interlayer 456 may include a magnetic material, such as a polycrystalline magnetic Heusler alloy. Magnetic Heusler alloys have large spin polarizations, and examples of magnetic Heusler alloys that can be used in the second interlayer 456 include Co2MnSb, Co2MnGe, CoMnSb, NiMnSb, Co2FeGe, Co2MnSn, and Co2MnFeGe, which do not mix easily with the BiSb layer 410. Figure 4B In the STO device 450, the thickness of the first interlayer 454 and the second interlayer 456 in the y direction is about to about between.

[0071] The nucleation layer 408 may include any of the same materials as the barrier layer 416 and / or the interlayer 412; or a nanocrystalline to polycrystalline epitaxial layer, such as a non-magnetic Heusler alloy; or a bcc or B2 non-interacting material with SOT. In addition, the nucleation layer 408 may include elements that do not easily interact with the Bi or Sb of the BiSb layer 410, such as Cu, Ag, Ge, Mn, Co, Ni, Mo, Sn, In, B and W; or a multi-element alloy combination thereof, such as CuAg, CuNi, CuCo and AgSn; or a low Fe alloy thereof, or one or more of these elements or combinations of elements. Other examples of materials that can be used as dust removal layers for the nucleation layer 408 include materials having a relative humidity of about 100%. to about The thickness of Ge is between about to about CuAg with a thickness between about to about The nucleation layer 408 may have a thickness of about to about Thickness.

[0072] The buffer layer 406 may comprise any one of the same materials as the barrier layer 416 and / or the interlayer 412. The buffer layer 406 may also comprise any one of the materials listed above for the interlayer 412, such as a single alloy layer or a combination of layers; a non-magnetic alloy or a multi-layer stack comprising one or more of the following elements Cu, Ag, Ge, Mn, Ni, Mo, and W; or a multi-element alloy combination thereof; or a combination with magnetic and / or non-magnetic alloys such as CoA, FeA, NiA, where A is one or more elements belonging to the full Heusler alloy X2YZ or the half-Heusler alloy XYZ, where X is selected from: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au; Y is selected from: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, and W; and Z is selected from: B, Al, Si, Ga, Ge, As, In, Sn, Sb, and Bi. The magnetic alloy or Heusler alloy should be combined with other elements such as Cu, Ag, Ge, Mn, Co, Ni, Mo, Sn, In, B, and W, or combined in their multi-element alloy layers to form a non-magnetic total stacked buffer layer 406. The buffer layer 406 can be thin or relatively thick, such as having a thickness of about to about in the y direction. A thicker buffer layer 406 can provide better migration resistance to the migration of elements from adjacent stacks into the BiSb layer 410, or provide better migration resistance to the migration of Bi or Sb out of the BiSb layer 410. The buffer layer 406 can be made thicker by laminating the layers to better control SOT nucleation / growth and texture.

[0073] Other examples of materials that can be used for the buffer layer 406 include: [Ge / X2YZ]*n stacks, [Ge / XYZ]*n stacks, and [Ge / XYZ]*n stacks, where n is an integer; Ge-rich X2YZ and Ge-rich XYZ single-layer alloys such that the buffer layer 406 is non-magnetic (i.e., Ge>44%); [Ge / Co2(MnFe)Ge *4, [Ge / CoFeGe *3, and [Ge / NiFe *n; and Ge alloyed or laminated with NiA, FeA, CoA in the lamination, where A is one or more elements belonging to the full Heusler alloy X2YZ or the half-Heusler alloy XYZ, for example, [Ge / NiA *n], where 1 < n < 4. The entire buffer layer 406 has a thickness between about and about .

[0074] In the SOT devices 400, 450, 500, the BiSb layer 410 is deposited on the buffer layer 406 or the nucleation layer 408. When the BiSb layer 410 is deposited, the BiSb layer 410 can be doped or remain undoped. When the BiSb layer 410 is undoped, the buffer layer 406 (or the nucleation layer 408) promotes the BiSb layer 410 to grow a (001) crystal orientation. When the BiSb layer 410 is doped, the buffer layer 406 (or the nucleation layer 408) promotes the BiSb layer 410 to grow a (012) crystal orientation. The relatively non-interacting dopant used to promote the (012) orientation of BiSb can be a gas, a metal, a non-metal, or a ceramic material. In order to produce a strong (012) texture, it is not necessary to dope the entire BiSb layer 410, only about the front of the BiSb layer 410 adjacent to the buffer layer 406 (or the nucleation layer 408) needs to be doped. to about The remaining BiSb layer 410 may then be deposited as undoped BiSb on top of the initially doped portion of the already deposited BiSb. Doping only a portion of the BiSb layer 410 is sufficient to promote and grow the (012) orientation of the entire BiSb layer 410. When the BiSb layer 410 has a (012) orientation or a (001) orientation, the SOT device 400 may achieve a spin Hall angle (SHA) of about 2 or greater.

[0075] An example of a BiSb doping process is described in co-pending patent application No. 17 / 854,568, filed on June 30, 2022, entitled “Novel Doping Process To Refined Grain Size For Smoother BiSb Film Surface,” which is assigned to the same assignee of the present application and is incorporated herein by reference.

[0076] about FIG. 4A to FIG. 5 In each of the SOT devices 400, 450, and 500, in some embodiments, each of the buffer layer 406, the barrier layer 416, and / or the interlayer 412 can be a single alloy layer. In other embodiments, each of the buffer layer 406, the barrier layer 416, and / or the interlayer 412 can be used as a thicker layer constructed by laminating repeating bilayers. The thicker laminated bilayer helps control the growth of (001) or (012) textured BiSb and reduces diffusion or migration through the buffer layer 406, the barrier layer 416, and / or the interlayer 412.

[0077] The buffer layer 406 and the nucleation layer 408 not only provide a strong (001) or (012) texture, but also inhibit the diffusion of Bi and Sb of the BiSb layer 410 into the buffer layer 406 and the nucleation layer 408 or minimize the migration through the buffer layer and the nucleation layer. Because the buffer layer 406, the nucleation layer 408 and / or the interlayer 412 have a high resistivity (e.g., about 300 μohm-cm), the shunting of the BiSb layer 410 is minimized and the SOT-FM intermixing is reduced, which in turn reduces the torque loss with the FM layer 414 and improves the thermal stability.

[0078] It should be further understood that multiple SOT devices 400 can be configured together as part of a memory cell array, wherein the BiSb layer 410 is a spin-track material electrode, wherein the top electrode 402b can be disposed above the cap layer 418; and multiple SOT devices 450 can be configured together as part of a memory cell array, wherein the BiSb layer 410 is a spin-track material electrode, wherein the top electrode (not shown) can be disposed above the cap layer 418; and multiple SOT devices 500 can be configured together as part of a memory cell array, wherein the BiSb layer 410 is a spin-track material electrode, wherein the top electrode (not shown) can be disposed above the cap layer 418. Each memory cell can be part of a two-terminal device or a three-terminal device. The spin-track material electrode and the top electrode can be used as a bit line, a word line, a read word line, a write word line, and combinations thereof. The memory cell array can be implemented as a cross-point array or other architecture.

[0079] As mentioned above, FIG. 4A to FIG. 5 Each of the SOT devices 400, 450 and 500 can be used as a BiSb STO device. A BiSb-based STO device, such as FIG. 4A to FIG. 5 The SOT devices 400, 450 and 500 generally have a larger SHA than conventional STO-based devices at the same input current density. For example, when both the conventional SOT device and the BiSb-based STO device have J=4×10 7 A / cm 2Conventional STOs typically have a SHA of about 0.4 when the input in-plane current density is 2, while BiSb-based STO devices have a SHA of about 2 or greater. As the applied magnetic field increases, the performance of conventional STO devices suffers because high frequencies cannot be achieved. Therefore, for conventional STO devices, the detected field range will be smaller due to the smaller SHA (e.g., 0.4). In addition, the signal sensitivity may be worse. Conventional STO devices with SHA 0.4 have a sensitivity of about 40 GHz / T, which is only slightly larger than the magneto-gyro ratio of about 28 GHz / T. However, in BiSb-based STO devices with SHA of 2 or greater, the linear relationship between the detection frequency and the applied magnetic field is extended over a larger dynamic range. In addition, the STO signal sensitivity can reach 100 GHz / T, which is at least twice as large as that of conventional STO readers. Therefore, the BiSb-based STO devices used in the read head have high performance.

[0080] Figure 6 A graph 600 showing the crystal orientation of BiSb layers for various SOT devices having a buffer layer, an interlayer, and a barrier layer each comprising a Heusler alloy according to one embodiment is shown. For example, the interlayer and barrier layer of each SOT device may comprise a specific FIG. 4A to FIG. 5 The BiSb layer may be any of the materials listed for the interlayer 412 and the barrier layer 416 of the SOT device 400, 450, 500, the BiSb layer may be the BiSb layer 410 of the SOT device 400, 450, 500, the interlayer may be the interlayer 412 of the SOT device 400, 450, 500, and the barrier layer may be the barrier layer 416 of the SOT device 400, 450, 500. In each of the SOT devices represented by lines 610-650, the SOT layer is BiSb doped with 5at.% CuAg (line 650 has a SOT layer that is approximately 10% thinner than lines 610-640). For lines 610 to 640, the SOT device includes a BiSb layer having approximately The NiFeTa seed layer has a thickness of about The FM layer containing CoFe and the FM layer containing [Ge / Co2(Mn 0.5 Fe 0.5 ) ]*4 and a buffer layer of a stack of Ge / X2YZ Heusler alloy, and NiFeTaN / CuAg The SOT device represented by line 650 includes a The NiFeTa seed layer has a thickness of about The RuAl texture layer has a thickness of about The thickness of the CoFe FM layer is about A MgO buffer layer having a thickness of about The seed layer may be the seed layer 404 of the SOT device 400 , 450 , 500 , the FM layer may be the FM layer 414 of the SOT device 400 , 450 , 500 , and the buffer layer may be the buffer layer 406 of the SOT device 400 , 450 , 500 .

[0081] In graph 600, line 610 represents a SOT device including an interlayer and a barrier layer: the interlayer comprises Ge / CoFe / CuAg, wherein Ge has about The thickness of CoFe is about The thickness of CuAg is about The barrier layer comprises Ge / CoFe / CuAg, wherein Ge has a thickness of about The thickness of CoFe is about The thickness of CuAg is about Line 620 represents a SOT device including an interlayer and a barrier layer, the interlayer comprising Ge / CoFe / CuAg, wherein Ge has a thickness of about The thickness of CoFe is about The thickness of CuAg is about The barrier layer comprises MgO, wherein the MgO has a thickness of about Line 630 represents a SOT device including an interlayer and a barrier layer, the interlayer comprising Ge / CoFe / NiFeTaN, wherein Ge has a thickness of about The thickness of CoFe is about The thickness of NiFeTaN is about The barrier layer comprises Ge / CoFe / CuAg, wherein Ge has a thickness of about The thickness of CoFe is about The thickness of CuAg is about Line 640 represents a SOT device including a CuAg / Ge / Co2FeGe / CuAg interlayer and a barrier layer including MgO, wherein CuAg has a thickness of about The thickness of Ge is about The thickness of Co2FeGe is about The thickness of CuAg is about The thickness of MgO is about The SOT device in line 650 consists of The MgO buffer layer and the interlayer composed of Ge / CoFe / MgO, in which Ge has The thickness of CoFe is The thickness of MgO is Thickness, no barrier layer.

[0082] As shown in each of lines 610-640, the BiSb layer achieves a higher (012) crystal orientation compared to a SOT device without a buffer layer, an interlayer, and a barrier layer including a Heusler alloy as one of the layers. Thus, using a Heusler alloy for the interlayer, barrier layer, and / or buffer layer enables the BiSb layer to achieve a strong (012) orientation.

[0083] Fig. 7A is a MAMR write head, such as can be used as Figure 1 Schematic cross-sectional view of a SOT device 700 for use in a MAMR write head that is a portion of a magnetic recording head of a drive 100 or other suitable magnetic media drive. The SOT device 700 includes a doped BiSb layer 410 having a (001) orientation or alternatively an undoped BiSb layer 410 having a (012) orientation, formed over a buffer layer 406 (or nucleation layer 408), formed over a shield or substrate 402, such as FIG. 4A to FIG. 5 The buffer layer 406 may include the BiSb layer 410 as described above. FIG. 4A to FIG. 5 The Heusler alloy described in , and has the same or similar properties as described above with respect to various embodiments. Spin torque layer (STL) 770 is formed above BiSb layer 410. STL 770 includes ferromagnetic materials, such as one or more layers of CoFe, CoIr, NiFe, and CoFeX alloys, where X = B, Ta, Re, or Ir. STL 770 can be a free layer, such as FIG. 3A to FIG. 3C Therefore, the STL 770 may also be referred to as a free layer.

[0084] In certain embodiments, the current shunt blocking layer 760 is disposed between the BiSb layer 410 and the STL 770. The current shunt blocking layer 760 reduces the current flowing from the BiSb layer 410 to the STL 770, but allows spin-orbit coupling of the BiSb layer 410 and the STL 770. In certain embodiments, the current shunt blocking layer 760 includes a magnetic material that provides greater spin-orbit coupling between the BiSb layer 410 and the STL 770 than a non-magnetic material. In certain embodiments, the current shunt blocking layer 760 comprises FeCo, FeCoM, FeCoMo, FeCoMMeO, FeCoM / MeO stack, FeCoMNiMnMgZnFeO, FeCoM / NiMnMgZnFeO stack, multiple layers / stacks thereof, or combinations thereof, wherein M is one or more of B, Si, P, Al, Hf, Zr, Nb, Ti, Ta, Mo, Mg, Y, Cu, Cr, and Ni, and Me is Si, Al, Hf, Zr, Nb, Ti, Ta, Mg, Y, or Cr. In certain embodiments, the current shunt blocking layer 760 is formed to about to about In some aspects, it has a thickness of more than The current shunt blocking layer 760 having a thickness of less than 1000 nm can reduce the spin-orbit coupling of the BiSb layer 410 and the STL 770. In some aspects, the current shunt blocking layer 760 having a thickness of less than 1000 nm can reduce the spin-orbit coupling of the BiSb layer 410 and the STL 770. A current-diverting blocking layer having a thickness of 200 Å may not be able to sufficiently reduce the current from the BiSb layer 410 to the STL 770 .

[0085] In some embodiments, additional layers such as spacer 780 and pinning layer 790 are formed over STL 770. Pinning layer 790 can partially pin STL 770. Pinning layer 790 can include a single layer or multiple layers of PtMn, NiMn, IrMn, IrMnCr, CrMnPt, FeMn, other antiferromagnetic materials, or combinations thereof. Spacer 780 includes a single layer or multiple layers of magnesium oxide, aluminum oxide, other non-magnetic materials, or combinations thereof.

[0086] FIG. 7B to FIG. 7C Is has Fig. 7A Schematic MFS view of some embodiments of a portion of a MAMR write head 210 of a SOT device 700. The MAMR write head 210 may be Figure 2 The write head in the Figure 1 The MAMR write head 210 includes a main pole 220 and a trailing shield 240 in the downtrack direction. The SOT device 700 is disposed in a gap between the main pole 220 and the trailing shield 240.

[0087] During operation, a charge current through the BiSb layer or layer stack 410 as a spin Hall layer generates a spin current in the BiSb layer. The spin-orbit coupling of the BiSb layer and the spin torque layer (STL) 770 causes the switching or precession of the magnetization of the STL 770 through the spin-orbit coupling of the spin current from the BiSb layer 410. The switching or precession of the magnetization of the STL 770 can generate an auxiliary AC electric field to the write field. Compared with the MAMR write head based on spin transfer torque, the energy-assisted write head based on SOT has a power efficiency several times greater. As Figure 7B As shown, due to the shape anisotropy of STL 770, Fig. 7A Due to the pinned layer 790 and / or the hard bias element near the STL 770, the easy axis of the magnetization direction of the STL 770 is perpendicular to the MFS. Figure 7C As shown, due to the shape anisotropy of STL 770, Fig. 7A Due to the pinned layer 790 and / or the hard bias element close to the STL 770, the easy axis of the magnetization direction of the STL 770 is parallel to the MFS.

[0088] Figure 8 8 is a schematic cross-sectional view of a SOT magnetic tunnel junction (MTJ) 801 used as an MRAM device 800. The MRAM device 800 includes a reference layer (RL) 810, a spacer layer 820 above the RL 810, a recording layer 830 above the spacer layer 820, a buffer layer 406 (or nucleation layer 408) above a current shunt blocking layer 840 above the recording layer 830, and a BiSb layer or layer stack 410 above the buffer layer 406. The BiSb layer 410 may be FIG. 4A to FIG. 5 The buffer layer 406 may include the BiSb layer 410 as described above. FIG. 4A to FIG. 5 and have the same or similar properties as described above with respect to various embodiments. The BiSb layer 410 may be a doped BiSb layer having a (012) orientation or an undoped BiSb layer having a (001) orientation. The RL 810 may be a free layer such as FIG. 3A to FIG. 3C Therefore, the RL 810 may also be referred to as a free layer.

[0089] RL 810 includes a single layer or multiple layers of CoFe, other ferromagnetic materials, or combinations thereof. Interlayer 820 includes a single layer or multiple layers of magnesium oxide, aluminum oxide, other dielectric materials, or combinations thereof. Recording layer 830 includes a single layer or multiple layers of CoFe, NiFe, other ferromagnetic materials, or combinations thereof.

[0090] As described above, in some embodiments, the current shunt blocking layer 840 is disposed between the buffer layer 406 and the recording layer 830. The current shunt blocking layer 840 reduces the current flowing from the BiSb layer 410 to the recording layer 830, but allows spin-orbit coupling of the BiSb layer 410 and the recording layer 830. For example, writing to the MRAM device can be achieved through spin-orbit coupling of the BiSb layer and the recording layer 830, which enables the magnetization of the recording layer 830 to be switched by spin-orbit coupling of the spin current from the BiSb layer 410. In some embodiments, the current shunt blocking layer 840 includes a magnetic material that provides greater spin-orbit coupling between the BiSb layer 410 and the recording layer 830 than a non-magnetic material. In certain embodiments, the current diversion blocking layer 840 comprises FeCoM, FeCoMo, FeCoMMeO, a FeCoM / MeO stack, a FeCoMNiMnMgZnFeO, a FeCoM / NiMnMgZnFeO stack, multiple layers / stacks thereof, or combinations thereof, wherein M is one or more of B, Si, P, Al, Hf, Zr, Nb, Ti, Ta, Mo, Mg, Y, Cu, Cr, and Ni, and Me is Si, Al, Hf, Zr, Nb, Ti, Ta, Mg, Y, or Cr.

[0091] Figure 8 The MRAM device 800 may include other layers, such as a pinning layer, a pinning structure (e.g., a synthetic antiferromagnetic (SAF) pinning structure), an electrode, a gate, and other structures. The MRAM device 800 may be formed using an undoped BiSb layer 410 having a (001) orientation or an alternatively doped BiSb layer 410 having a (012) orientation over the buffer layer 406. Figure 8 The structure is other than the MRAM device to form the SOT MTJ 801.

[0092] Therefore, when one or more of the buffer layer, interlayer, barrier layer, and nucleation layer of the SOT device comprises an amorphous / nanocrystalline Heusler alloy or a polycrystalline Heusler alloy alloyed with other elements that are not easily mixed with the BiSb layer, such layers have high resistance and reduce intermixing of the interlayer / barrier layer with the BiSb layer or with the FM layer. Heusler alloys generally have higher resistivity than the FM layer and transmit spin current or high spin polarization while providing and maintaining (100) growth. Heusler alloys also have excellent lattice matching capabilities with MgO tunnel barrier layers and bcc FM alloys. The (100) texture layer can be used to establish a (100) texture, and the non-magnetic Heusler X2YZ or XYZ with cF16 (C1b, L21) or B2 structure can be used to transfer the texture to the BiSb layer, which in turn grows a strong (012) texture for the BiSb layer and a strong (100) texture for the FM layer. Therefore, one or more of the buffer layer, interlayer, barrier layer, and nucleation layer of the SOT device includes an amorphous / nanocrystalline Heusler alloy or a polycrystalline Heusler alloy alloyed with other elements that are not easily mixed with the BiSb layer, so that the SOT device has improved overall performance.

[0093] In one embodiment, the SOT device includes a first non-magnetic layer and a bismuth antimony (BiSb) layer, wherein the first non-magnetic layer comprises a Heusler alloy and a material selected from Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B and In, and the BiSb layer is arranged in contact with the first non-magnetic layer.

[0094] The SOT device also includes a second non-magnetic layer comprising a Heusler alloy and a material selected from the group consisting of Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In. The second non-magnetic layer is disposed in contact with the BiSb layer. The first non-magnetic layer is a buffer layer, and the second non-magnetic layer is an interlayer. The interlayer has a value less than or equal to about The thickness of the buffer layer is about 5 to about The SOT device also includes a third non-magnetic layer and a ferromagnetic layer, the third non-magnetic layer comprising a Heusler alloy and a material selected from Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B and In, and the ferromagnetic layer is arranged in contact with the third non-magnetic layer. The first non-magnetic layer is also arranged in contact with the ferromagnetic layer. The Heusler alloy is a full Heusler alloy containing X2YZ, wherein X is selected from: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt and Au, Y is selected from: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf and W, and Z is selected from: B, Al, Si, Ga, Ge, As, In, Sn, Sb and Bi. The Heusler alloy is a semi-Heusler alloy comprising XYZ, wherein X is selected from the group consisting of: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt and Au, Y is selected from the group consisting of: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf and W, and Z is selected from the group consisting of: B, Al, Si, Ga, Ge, As, In, Sn, Sb and Bi. The polycrystalline non-Heusler alloy material is selected from the group consisting of: NiAl, RuAl, RhAl, Mn3Al, V, Mo, W, TiW, CrX, wherein x=Ti, Ru, Mo or W; CrMo, CrMoTi, Cr, MoV, CrMoW, wherein Mo is between about 20 atomic percent and about 50 atomic percent; V2VAl; and CrXY, wherein X and Y are each independently selected from the group consisting of: Al, Ti, Mn, Co, Ni, Ru, Mo, Rh, W and V. A magnetic recording head, the magnetic recording head comprises the SOT device. A magnetic recording device, the magnetic recording device comprises the magnetic recording head. A magnetoresistive memory, the magnetoresistive memory comprises the SOT device. A magnetic sensor, the magnetic sensor comprises the SOT device.

[0095] In another embodiment, a SOT device includes: a textured layer, a non-magnetic buffer layer disposed on the textured layer, a bismuth antimony (BiSb) layer above the non-magnetic buffer layer, a non-magnetic interlayer disposed on the BiSb layer, a ferromagnetic layer disposed on the non-magnetic interlayer, and a non-magnetic barrier layer disposed on the ferromagnetic layer, wherein one or more of the non-magnetic barrier layer, the non-magnetic interlayer, and the non-magnetic buffer layer comprises a Heusler alloy and a material selected from Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In.

[0096] Each of the nonmagnetic barrier layer, the nonmagnetic interlayer and the nonmagnetic buffer layer comprises a Heusler alloy and a material selected from Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B and In. The SOT device also includes a nucleation layer disposed between the nonmagnetic buffer layer and the BiSb layer, the nucleation layer comprising a Heusler alloy and a material selected from Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B and In. The Heusler alloy is a full Heusler alloy comprising X2YZ, wherein X is selected from: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt and Au, Y is selected from: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf and W, and Z is selected from: B, Al, Si, Ga, Ge, As, In, Sn, Sb and Bi. The Heusler alloy is a half-Heusler alloy comprising XYZ, wherein X is selected from the group consisting of: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au, Y is selected from the group consisting of: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, and W, and Z is selected from the group consisting of: B, Al, Si, Ga, Ge, As, In, Sn, Sb, and Bi. The SOT device also includes an amorphous seed layer disposed in contact with the texture layer and a cap layer disposed on the nonmagnetic barrier layer. The polycrystalline non-Heusler alloy material is selected from: NiAl, RuAl, RhAl, Mn3Al, V, Mo, W, TiW, CrX, where x=Ti, Ru, Mo or W; CrMo, CrMoTi, Cr, MoV, CrMoW, where Mo is between about 20 atomic percent and about 50 atomic percent; V2VAl; and CrXY, where X and Y are each individually selected from: Al, Ti, Mn, Co, Ni, Ru, Mo, Rh, W and V. A magnetic recording head, the magnetic recording head includes the SOT device. A magnetic recording device, the magnetic recording device includes the magnetic recording head. A magnetoresistive memory, the magnetoresistive memory includes the SOT device. A magnetic sensor, the magnetic sensor includes the SOT device.

[0097] In yet another embodiment, a SOT device includes a seed layer, a textured layer disposed on the seed layer, a ferromagnetic layer disposed on the textured layer, a nonmagnetic buffer layer disposed on the ferromagnetic layer, a bismuth antimony (BiSb) layer above the nonmagnetic buffer layer, and a nonmagnetic interlayer disposed on the BiSb layer, wherein one or more of the nonmagnetic interlayer and the nonmagnetic buffer layer comprises a Heusler alloy and a material selected from the group consisting of Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In.

[0098] Each of the nonmagnetic interlayer and the nonmagnetic buffer layer comprises a Heusler alloy and a material selected from Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In. The Heusler alloy is a full Heusler alloy comprising X2YZ, wherein X is selected from the group consisting of: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au, Y is selected from the group consisting of: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, and W, and Z is selected from the group consisting of: B, Al, Si, Ga, Ge, As, In, Sn, Sb, and Bi. The Heusler alloy is a semi-Heusler alloy comprising XYZ, wherein X is selected from the group consisting of: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt and Au, Y is selected from the group consisting of: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf and W, and Z is selected from the group consisting of: B, Al, Si, Ga, Ge, As, In, Sn, Sb and Bi. The polycrystalline non-Heusler alloy material is selected from the group consisting of: NiAl, RuAl, RhAl, Mn3Al, V, Mo, W, TiW, CrX, wherein x=Ti, Ru, Mo or W; CrMo, CrMoTi, Cr, MoV, CrMoW, wherein Mo is between about 20 atomic percent and about 50 atomic percent; V2VAl and CrXY, wherein X and Y are each independently selected from the group consisting of: Al, Ti, Mn, Co, Ni, Ru, Mo, Rh, W and V. A magnetic recording head, the magnetic recording head comprises the SOT device. A magnetic recording device, the magnetic recording device comprises the magnetic recording head. A magnetoresistive memory, the magnetoresistive memory comprises the SOT device. A magnetic sensor, the magnetic sensor comprises the SOT device.

[0099] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be envisaged without departing from the basic scope of the present disclosure, and the scope of the present disclosure is determined by the appended claims.

Claims

1. A spin-orbit torque (SOT) device, comprising: a first nonmagnetic layer comprising a polycrystalline non-Heusler alloy material, or a Heusler alloy and a material selected from the group consisting of Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In; and A bismuth antimony (BiSb) layer is provided in contact with the first non-magnetic layer.

2. The SOT device according to claim 1, further comprising a second non-magnetic layer, the second non-magnetic layer comprising a Heusler alloy and a material selected from the group consisting of Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B and In. 3 . The SOT device according to claim 2 , wherein the second nonmagnetic layer is provided in contact with the BiSb layer. 4 . The SOT device according to claim 2 , wherein the first nonmagnetic layer is a buffer layer, and wherein the second nonmagnetic layer is an interlayer.

5. The SOT device according to claim 4, wherein the interlayer has a thickness less than or equal to about The thickness of the buffer layer is about to about The thickness between.

6. The SOT device according to claim 1, further comprising: a third nonmagnetic layer comprising a Heusler alloy and a material selected from the group consisting of Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In; and A ferromagnetic layer is provided in contact with the third non-magnetic layer. 7 . The SOT device according to claim 6 , wherein the first non-magnetic layer is further provided in contact with the ferromagnetic layer.

8. The SOT device of claim 1 , wherein the Heusler alloy is a full Heusler alloy comprising X2YZ, wherein X is selected from the group consisting of: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au, Y is selected from the group consisting of: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, and W, and Z is selected from the group consisting of: B, Al, Si, Ga, Ge, As, In, Sn, Sb, and Bi.

9. The SOT device of claim 1 , wherein the Heusler alloy is a half-Heusler alloy comprising XYZ, wherein X is selected from the group consisting of: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au, Y is selected from the group consisting of: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, and W, and Z is selected from the group consisting of: B, Al, Si, Ga, Ge, As, In, Sn, Sb, and Bi.

10. The SOT device according to claim 1, wherein the polycrystalline non-Heusler alloy material is selected from: NiAl, RuAl, RhAl, Mn3Al, V, Mo, W, TiW, CrX, among which x=Ti, Ru, Mo or W; CrMo, CrMoTi, Cr, MoV, CrMoW, wherein Mo is between about 20 atomic % and about 50 atomic %; V2VA1; and CrXY, wherein X and Y are each independently selected from: Al, Ti, Mn, Co, Ni, Ru, Mo, Rh, W and V. 11 . A magnetic recording head comprising the SOT device according to claim 1 .

12. A magnetic recording apparatus comprising the magnetic recording head according to claim 11. 13 . A magnetoresistive memory, comprising the SOT device according to claim 1 . 14 . A magnetic sensor comprising the SOT device according to claim 1 .

15. A spin-orbit torque (SOT) device, the SOT device comprising: Texture layer; a non-magnetic buffer layer disposed on the texture layer; a bismuth antimony (BiSb) layer over the nonmagnetic buffer layer; A nonmagnetic interlayer disposed on the BiSb layer; a ferromagnetic layer disposed on the nonmagnetic interlayer; and A non-magnetic barrier layer disposed on the ferromagnetic layer, wherein one or more of the nonmagnetic barrier layer, the nonmagnetic interlayer, and the nonmagnetic buffer layer comprises a polycrystalline non-Heusler alloy material, or a Heusler alloy and a material selected from Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In.

16. The SOT device of claim 15, wherein each of the nonmagnetic barrier layer, the nonmagnetic interlayer, and the nonmagnetic buffer layer comprises a Heusler alloy and a material selected from the group consisting of Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In.

17. The SOT device according to claim 15, further comprising a nucleation layer disposed between the nonmagnetic buffer layer and the BiSb layer, the nucleation layer comprising a Heusler alloy and a material selected from the group consisting of Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B and In.

18. The SOT device of claim 15, wherein the Heusler alloy is a full Heusler alloy comprising X2YZ, wherein X is selected from the group consisting of: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au, Y is selected from the group consisting of: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, and W, and Z is selected from the group consisting of: B, Al, Si, Ga, Ge, As, In, Sn, Sb, and Bi.

19. The SOT device of claim 15, wherein the Heusler alloy is a half-Heusler alloy comprising XYZ, wherein X is selected from the group consisting of: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au, Y is selected from the group consisting of: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, and W, and Z is selected from the group consisting of: B, Al, Si, Ga, Ge, As, In, Sn, Sb, and Bi.

20. The SOT device according to claim 15, wherein the polycrystalline non-Heusler alloy material is selected from: NiAl, RuAl, RhAl, Mn3Al, V, Mo, W, TiW, CrX, among which x=Ti, Ru, Mo or W; CrMo, CrMoTi, Cr, MoV, CrMoW, wherein Mo is between about 20 atomic % and about 50 atomic %; V2VA1; and CrXY, wherein X and Y are each independently selected from: Al, Ti, Mn, Co, Ni, Ru, Mo, Rh, W and V.

21. The SOT device according to claim 15, further comprising: an amorphous seed layer disposed in contact with the texture layer; and A covering layer is disposed on the non-magnetic barrier layer.

22. A magnetic recording head comprising the SOT device according to claim 15.

23. A magnetic recording apparatus comprising the magnetic recording head according to claim 22. 24 . A magnetoresistive memory, comprising the SOT device according to claim 15 . 25 . A magnetic sensor comprising the SOT device according to claim 15 .

26. A spin-orbit torque (SOT) device, the SOT device comprising: Seed layer; a texture layer disposed on the seed layer; a ferromagnetic layer disposed on the texture layer; a non-magnetic buffer layer disposed on the ferromagnetic layer; a bismuth antimony (BiSb) layer over the nonmagnetic buffer layer; and A nonmagnetic interlayer disposed on the BiSb layer, One or more of the nonmagnetic interlayer and the nonmagnetic buffer layer comprises a polycrystalline non-Heusler alloy material, or a Heusler alloy and a material selected from Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B and In.

27. The SOT device of claim 26, wherein each of the nonmagnetic interlayer and the nonmagnetic buffer layer comprises a Heusler alloy and a material selected from the group consisting of Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In.

28. The SOT device of claim 26, wherein the Heusler alloy is a full Heusler alloy comprising X2YZ, wherein X is selected from the group consisting of: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au, Y is selected from the group consisting of: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, and W, and Z is selected from the group consisting of: B, Al, Si, Ga, Ge, As, In, Sn, Sb, and Bi.

29. The SOT device of claim 26, wherein the Heusler alloy is a half-Heusler alloy comprising XYZ, wherein X is selected from the group consisting of: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au, Y is selected from the group consisting of: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, and W, and Z is selected from the group consisting of: B, Al, Si, Ga, Ge, As, In, Sn, Sb, and Bi.

30. The SOT device of claim 26, wherein the polycrystalline non-Heusler alloy material is selected from: NiAl, RuAl, RhAl, Mn3Al, V, Mo, W, TiW, CrX, among which x=Ti, Ru, Mo or W; CrMo, CrMoTi, Cr, MoV, CrMoW, wherein Mo is between about 20 atomic % and about 50 atomic %; V2VA1; and CrXY, wherein X and Y are each independently selected from: Al, Ti, Mn, Co, Ni, Ru, Mo, Rh, W and V.

31. A magnetic recording head comprising the SOT device according to claim 26.

32. A magnetic recording apparatus comprising the magnetic recording head according to claim 31.

33. A magnetoresistive memory, comprising the SOT device according to claim 26.

34. A magnetic sensor comprising the SOT device according to claim 26.

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