CRYSTALLIZED YPtBi (111) TOPOLOGICAL SEMI-METAL (TSM) INDUCED BY (111) OR (002)-(111) BUFFERS

Abstract

The present disclosure generally relates to spintronic devices comprising a YPtBi layer having a (111 ) orientation. The spintronic stack further comprises a ferromagnetic layer and a buffer layer. The buffer layer has a (002) or (111 ) orientation, which promotes the (111 ) orientation of the YPtBi layer. The buffer layer comprises an amorphous oxide or nitride layer, an amorphous metal layer disposed on the amorphous oxide or nitride layer, a textured pre-seed layer disposed on the amorphous metal layer, and one of: a (002) hexagon or (111) fee layer, a B2 alloy layer, or first and second bcc or B2 alloy layers.

Description

Crystallized YPtBi (111) Topological Semi-Metal (TSM) Induced by (111) or (002)-(111) BuffersBACKGROUND OF THE DISCLOSUREField of the Disclosure

[0001] Embodiments of the present disclosure generally relate to spintronic devices with a textured buffer layer for growing a topological semi-metal (TSM) material.Description of the Related Art

[0002] Spintronic devices have been used in various sensor, data storage, memory, and logic applications, and have shown promise in recent years to support devices for artificial intelligence applications. Various materials have been attempted in the search for efficient spin Hall effect (SHE) materials for such devices, among which are various topological insulator materials with high spin Hall angles.

[0003] YPtBi layers are narrow band gap topological semi-metals having both giant spin Hall effect and good thermal robustness. YPtBi is a material that has been proposed in various spin-orbit torque (SOT) device applications, such as for a spin Hall layer for magnetoresistive random access memory (MRAM) devices, magnetic recording read heads, sensors, and energy-assisted magnetic recording (EAMR) magnetic recording heads. However, utilizing YPtBi materials in commercial SOT applications can present several obstacles. For example, YPtBi materials require specific buffer layers and / or interlayers, as well as optimal processing conditions, to achieve the desired orientation.

[0004] Therefore, there is a need for an improved SOT device utilizing TSM layer(s) having a desired (111) crystal orientation.Docket No: WESD / 0985USL (WDA-7822-WO)PCT-Application_WDA-7822-WOSUMMARY OF THE DISCLOSURE

[0005] The present disclosure generally relates to spintronic devices comprising a YPtBi layer having a (111 ) orientation. The spintronic stack further comprises a ferromagnetic layer and a buffer layer. The buffer layer has a (002) or (111 ) orientation, which promotes the (111 ) orientation of the YPtBi layer. The buffer layer comprises an amorphous oxide or nitride layer, an amorphous metal layer disposed on the amorphous oxide or nitride layer, a textured pre-seed layer disposed on the amorphous metal layer, and one of: a (002) hexagon or (111 ) fee layer, a B2 alloy layer, or first and second bcc or B2 alloy layers.

[0006] In one embodiment, a spintronic stack comprises a YPtBi layer having a (111 ) orientation, a ferromagnetic layer, and a buffer layer, the buffer layer comprising: an amorphous oxide or nitride layer, an amorphous metal layer disposed on the amorphous oxide or nitride layer, a textured pre-seed layer disposed on the amorphous metal layer, and a (002) hexagonal or (111 ) fee layer disposed on the textured pre-seed layer, the (002) hexagonal or (111 ) fee layer having a-axis lattice parameters around 4.6 A to 4.8 A when the (002) hexagonal or (111 ) fee layer has a (002) hexagonal orientation, the (002) hexagonal or (111 ) fee layer having a (002) hexagonal orientation comprising an alloy material selected from the group consisting of: Fe2X, where X is one of Ti, Mo, Ta, or TazWi-z, (where z is a numeral between 0.005 and 1 ), C02X alloys, where X is one of Ti, Nb, Ta, TaAl, or NbAI, and (CoFe)2Ta. A number of the C02X alloys exist both as hexagonal and fee phases. The (111 ) fee materials of the (002) hexagonal or (111 ) fee layer have a-axis lattice parameters in the range of about 6.6 A to about 6.8 A where (cF24 - space group Fd-3m) materials are selected from the group consisting of: C02X, where X is one of Ti, Nb, Ta, Hf, or Zr, (cF24 - space group F-43m materials), NisHf, and XsZr alloys, where X is one of Co, Ni, NiFe, or CuNi. There are also fee (111 ) ternary alloys (cF12 - space group F- 43m) having a-axis lattice parameters in the range of about 6.4 A to 6.7 A thatDocket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOcan used as buffer layers, such as AuScSn, BiCoZr, BiNiY, or Bi-XQ alloys, where X is one of Ni, Pt, and Q is a rare earth, such as Gd and Dy.

[0007] In another embodiment, a spintronic stack comprises a YPtBi layer having a (111 ) orientation, a ferromagnetic layer, and a buffer layer, the buffer layer comprising: an amorphous oxide or nitride layer, an amorphous metal layer disposed on the amorphous oxide or nitride layer, a textured pre-seed layer disposed on the amorphous metal layer, and a B2 or bcc alloy layer disposed on the textured pre-seed layer, the B2 or bcc alloy layer with a-axis lattice parameter of about 3.1 A to about 3.4 A comprising a material selected from the group consisting of: MgAu, Sc-X, where X is one of Al, Ni, Pd, or Au, Ti-X, where X is one of Ru, RuTi, Rh, Pd, Pt, or Au, Ru-X where X is one of Ti or Ta, TaxWi-x(where x is a numeral between 0.005 and 1 ), Ir-X, where X is one of Sc, Ti, Y, or Zr, Hf-X, where X is one of Co, Ni, Ru, Pt, Zr-X, where X is one of Co, Cu, Rh, Ru, and Os, and B2-alloy ternaries including (AIMo).sTi, (AIV).sRu, (AIZr).sRu, (HfTi).5Ru, (Co4Ni).2Zr, (Co4Fe).2Zr, and (NbZr3).25Co.

[0008] In yet another embodiment, a spintronic stack comprises a YPtBi layer having a (111 ) orientation, a ferromagnetic layer, and a buffer layer, the buffer layer comprising: an amorphous oxide or nitride layer, an amorphous metal layer disposed on the amorphous oxide or nitride layer, a textured pre-seed layer disposed on the amorphous metal layer, a first bcc or B2 alloy with slightly lower a-axis lattice parameter layer disposed on the textured pre-seed layer, the first bcc or B2 alloy layer comprising a material selected from the group consisting of: RuTi, RhTi, (HfTi) 5Ru, (Co4Ni)2Zr, and (Co4Fe)2Zr, and a second bcc or B2 layer with a slightly higher a-axis lattice parameter disposed on the first bcc or B2 layer, the second bcc or B2 layer comprising a material selected from the group consisting of: Zr-X, where X is one of Co, Cu, Ru, Rh, or Os, Ir-X, where X is one of Sc, Y, or Zr, and TaxWi-x(where x is a numeral between 0.005 and 1 ).Docket No: WESD / 0985USL (WDA-7822-WO)PCT-Application_WDA-7822-WOBRIEF DESCRIPTION OF THE DRAWINGS

[0009] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

[0010] Figure 1 is a schematic illustration of certain embodiments of a magnetic media drive including a magnetic recording head with a spintronic device.

[0011] Figure 2 is a fragmented, cross-sectional view of certain embodiments of a read / write head with a spintronic device.

[0012] Figure 3A is a schematic illustration of a forward spintronic material stack, according one embodiment.

[0013] Figure 3B is a schematic illustration of a reverse spintronic material stack, according another embodiment.

[0014] Figures 4A-4D illustrate various buffer layers for use in the spintronic stacks of Figures 3A-3B, according to various embodiments.

[0015] Figure 5A is a schematic cross-sectional view of a SOT device for use in a MAMR magnetic recording head, such as the MAMR magnetic recording head of the drive of Figure 1 or other suitable magnetic media drives.

[0016] Figures 5B-5C are schematic MFS views of certain embodiments of a portion of a MAMR magnetic recording head with a SOT device of Figure 5A.Docket No: WESD / 0985USL (WDA-7822-WO)PCT-Application_WDA-7822-WO

[0017] Figure 6 is a schematic cross-sectional view of a SOT MTJ used as a MRAM device.

[0018] Figure 7 illustrates a schematic of a simplified deep neural network (DNN) or logic device, according to one embodiment.

[0019] Figure 8 illustrates a spin orbital-spin orbital (SO-SO) device, according to one embodiment.

[0020] 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

[0021] In the following, reference is made to embodiments of the disclosure. However, it should be understood that the disclosure is not limited to specific described embodiments. Instead, any combination of the following features and elements, whether related to different embodiments or not, is contemplated to implement and practice the disclosure. Furthermore, although embodiments of the disclosure may achieve advantages over other possible solutions and / or over the prior art, whether or not a particular advantage is achieved by a given embodiment is not limiting of the disclosure. Thus, the following aspects, features, embodiments and advantages are merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in a claim(s). Likewise, reference to “the disclosure” shall not be construed as a generalization of any inventive subject matter disclosed herein and shall not be considered to be an element or limitation of the appended claims except where explicitly recited in a claim(s).Docket No: WESD / 0985USL (WDA-7822-WO)PCT-Application_WDA-7822-WO

[0022] The present disclosure generally relates to spintronic devices comprising a YPtBi layer having a (111 ) orientation. The spintronic stack further comprises a ferromagnetic layer and a buffer layer. The buffer layer has a (002) or (111 ) orientation, which promotes the (111 ) orientation of the YPtBi layer. The buffer layer comprises an amorphous oxide or nitride layer, an amorphous metal layer disposed on the amorphous oxide or nitride layer, a textured pre-seed layer disposed on the amorphous metal layer, and one of: a (002) hexagon or (111 ) fee layer, a B2 alloy layer, or first and second bcc or B2 alloy layers.

[0023] Figure 1 is a schematic illustration of certain embodiments of a magnetic media drive 100 including a magnetic recording head with a SOT device. Such a magnetic media drive may be a single drive or comprise multiple drives. For illustration, a single disk drive 100 is shown according to certain embodiments. As shown, at least one rotatable magnetic disk 112 is supported on a spindle 114 and rotated by a drive motor 118. The magnetic recording on each magnetic disk 112 is in the form of any suitable patterns of data tracks, such as annular patterns of concentric data tracks (not shown) on the magnetic disk 112.

[0024] At least one slider 113 is positioned near the magnetic disk 112, and each slider 113 supports one or more magnetic head assemblies 121 , including a SOT device. As the magnetic disk 112 rotates, the slider 113 moves radially in and out over the disk surface 122 so that the magnetic head assembly 121 may access different tracks of the magnetic disk 112 where desired data are written. Each slider 113 is attached to an actuator arm 119 by a suspension 115. The suspension 115 provides a slight spring force which biases the slider 113 toward the disk surface 122. Each actuator arm 119 is attached to an actuator means 127. The actuator means 127, as shown in Figure 2, may be a voice coil motor (VCM). The VCM includes a coil movable within a fixed magnetic field, theDocket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOdirection and speed of the coil movements being controlled by the motor current signals supplied by the control unit 129.

[0025] During operation of the disk drive 100, the rotation of the magnetic disk112 generates an air bearing between the slider 113 and the disk surface 122 which exerts an upward force or lift on the slider 113. The air bearing thus counterbalances the slight spring force of suspension 115, and supports slider113 off and slightly above the disk surface 122 by a small, substantially constant spacing during regular operation.

[0026] The various components of the disk drive 100 are operated by control signals generated by control unit 129, such as access control signals and internal clock signals. The control unit 129 typically comprises logic control circuits, storage means, and a microprocessor. The control unit 129 generates control signals to 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 profiles to move optimally and position slider 113 to the desired data track on disk 112. Write and read signals are communicated to and from write and read heads on the assembly 121 by recording channel 125.

[0027] The above description of a typical magnetic media drive and the accompanying illustration of Figure 1 are for representation purposes only. It should be apparent that magnetic media drives may contain a large number of media, or disks, and actuators, and each actuator may support a number of sliders.

[0028] It is to be understood that the embodiments discussed herein are applicable to a data storage device such as a hard disk drive (HDD) as well as a tape drive such as a tape embedded drive (TED) or an insertable tape media drive. An example TED is described in co-pending patent application titled “TapeDocket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOEmbedded Drive,” United States App. No. 16 / 365,034, filed 3 / 31 / 19, assigned to the same assignee of this application, which is herein incorporated by reference. As such, any reference in the detailed description to an HDD or tape drive is merely for exemplification purposes and is not intended to limit the disclosure unless explicitly claimed. For example, references to disk media in an HDD embodiment are provided as examples only, and can be substituted with tape media in a tape drive embodiment. Furthermore, reference to or claims directed to magnetic recording devices or data storage devices are intended to include at least both HDD and tape drive unless HDD or tape drive devices are explicitly claimed.

[0029] Figure 2 is a fragmented, cross-sectional side view of certain embodiments of a read / write head 200 having a SOT device. The read / write head 200 faces a magnetic media 112. The read / write head 200 may correspond to the magnetic head assembly 121 described in Figure 1. The read / write head 200 includes a media facing surface (MFS) 212, such as a gas bearing surface, facing the disk 112, a write head 210, and a magnetic read head 211. As shown in Figure 2, the magnetic media 112 moves past the write head210 in the direction indicated by the arrow 232, and the read / write head 200 moves in the direction indicated by the arrow 234.

[0030] In some embodiments, the magnetic read head 211 is a magnetoresistive (MR) read head with an MR sensing element 204 located between MR shields S1 and S2. In other embodiments, the magnetic read head211 is a magnetic tunnel junction (MTJ) read head that includes an MTJ sensing device 204 disposed between MR shields S1 and S2. The magnetic fields of the adjacent magnetized regions in the magnetic disk 112 are detectable by the MR (or MTJ) sensing element 204 as the recorded bits. The SOT device of various embodiments can be incorporated into the read head 211 as the sensing element. An example of a SOT read head is described in a co-pending patentDocket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOapplication titled “Topological Insulator Based Spin Torque Oscillator Reader,” United States App. No. 17 / 828,226, filed May 31 , 2022, assigned to the same assignee of this application, which is herein incorporated by reference. Another example of a SOT read head is described in co-pending patent applications titled “Non-Localized Spin Valve Reader Hybridized With Spin Orbit Torque Layer,” United States App. No. 18 / 367,877, filed September 13, 2023, and “Non- Localized Spin Valve Multi-Free-Layer Reader Hybridized With Spin Orbit Torque Layers,” United States App. No. 18 / 367,882, filed September 13, 2023, which is herein incorporated by reference.

[0031] The write head 210 includes a central or main pole 220, a leading shield 206, a trailing shield 240, an optional spin-orbital torque (SOT) device 250, and a coil 218 that excites the main pole 220. The coil 218 may have a “pancake” structure that winds around a back-contact between the main pole 220 and the trailing shield 240, instead of a “helical” structure shown in Figure 2. For example, when included, e.g., to achieve a Microwave Assisted Magnetic Recording (MAMR) effect, the SOT device 250 is formed in a gap 254 between the main pole 220 and the trailing shield 240. In certain embodiments, the read / write head 200 additionally includes mechanisms (not shown) for supporting Heat Assisted Magnetic Recording (HAMR), which may include a waveguide coupled to a light source and a near field transducer (NFT) placed adjacent to the main pole 220 and coupled to the waveguide to convert the delivered light into a heating spot on the media.

[0032] The main pole 220 includes a trailing taper 242 and a leading taper 244. The trailing taper 242 extends from a location recessed from the MFS 212 to the MFS 212. The leading taper 244 extends from a location recessed from the MFS 212 to the MFS 212. The trailing taper 242 and the leading taper 244 may have the same degree of taper, and the degree of taper is measured with respect to a longitudinal axis 260 of the main pole 220. In some embodiments,Docket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOthe main pole 220 does not include the trailing taper 242 and the leading taper 244. Instead, the main pole 220 includes a trailing side (not shown) and a leading side (not shown), and the trailing side and the leading side are substantially parallel. The main pole 220 may be a magnetic material, such as a FeCo alloy. The leading shield 206 and the trailing shield 240 may comprise magnetic materials, such as a NiFe alloy.

[0033] Figure 3A is a schematic illustration of a forward spintronic material stack 300, according one embodiment. Figure 3B is a schematic illustration of a reverse spintronic material stack 350, according another embodiment. Each spintronic stack 300, 350 may be utilized in the magnetic media drive 100 of Figure 1 , in the reader, and / or writer portions of the head 200 of Figure 2, or other suitable magnetic media drives. Each spintronic stack 300, 350 may be utilized in a magnetic memory (such as MRAM) cell or logic cell. Aspects of the spintronic stacks 300, 350 may be used in combination with one another.

[0034] The spintronic stack 300 of Figure 3A comprises an amorphous layer 302, a buffer layer 304 disposed over the amorphous layer 302, a topological semi-metal (TSM) layer 310 disposed over the buffer layer 304, an optional interlayer 312 disposed over the TSM layer 310, a ferromagnetic (FM) layer 314 disposed over the interlayer 312 or the TSM layer 310, and a cap layer 316 disposed on the FM layer 314. The TSM layer 310 may be referred to herein as a spin orbit torque (SOT) layer 310. While not shown, the amorphous layer 302 may be disposed on a seed layer. The buffer layer 304 may be a multilayer structure, as discussed further below. The buffer layer 304 and the interlayer 312 each individually comprises high resistivity materials.

[0035] The spintronic stack 350 of Figure 3B is similar to the spintronic stack 300 of Figure 3A; however, the layers of the spintronic stack 350 are ordered differently. The spintronic stack 350 comprises the amorphous layer 302, the buffer layer 304 disposed on the amorphous layer 302, the FM layer 314 Docket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOdisposed on the buffer layer 304, the optional interlayer 312 disposed on the FM layer 314, the TSM layer 310 disposed on the interlayer 312 or the FM layer 314, a barrier layer 308 disposed on the TSM layer 310, and the cap layer 316 disposed on the barrier layer 308.

[0036] The buffer layer 304, the barrier layer 308, and the interlayer 312 help minimize shunting, act as migration barriers, and function as crystal symmetry transfer layers to promote or provide the (111 ) orientation to the TSM layer 310. The buffer layer 304 may be a multilayer structure, as discussed further below in Figures 4A-4C.

[0037] The amorphous layer 302 comprises a metal amorphous layer, such as CoFeTaN, NiTa NiW, NiFeTa, NiFeW, CoFeTa, or NiFeGe, or a bilayer amorphous metal oxide / metal amorphous layer, such as AhOs / CoFeTaN, which may have a high resistance property, (7” denotes separate sub-layers). In some embodiments, the amorphous layer 302 comprises CoFeTaN. The amorphous layer 302 has a thickness in y-direction of about 10 A to about 50 A. The TSM layer 310 comprises YPtBi having (111) orientation. In some embodiments, the TSM layer 310 comprises YPtBiX, where X is a dopant. The TM layer 310 has a thickness in the y-direction of about 50 A to about 200 A.

[0038] The barrier layer 308 comprises one or more materials selected from the group consisting of: X-AIGe, X-AIGeN (where Ge is about 0.5 at. % to about 50 at. % and N is less than about 20 at. %), HfN, TiN, NiFeGe, NiFeGeN, TaxWi- xN, and TaxHfi-xN (for nitrides of Ti, Hf, TaW, and TaHf, the N can be stoichiometric or nonstoichiometric). The material of the barrier layer 308 may be crystalline. In one embodiment, the barrier layer 308 comprises a first sublayer of HfN, and a second sublayer of TiN, or a first sublayer comprising MgO, and a second sublayer comprising NiGeAIN or IrAIGeN. The barrier layer 308 has a total thickness in the y-direction of about 3 A to about 20 A. When materials are written in the form of X-Q, the dash (-) indicates the material is an alloy.Docket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WO

[0039] The optional interlayer 312 comprises one or more materials selected from the group consisting of: stoichiometric or non-stoichiometric SiN, AIN, TiN, CrN, ZrN, MgO, MgTiO, MgAIO, TiO, TiN, HfN, X-QGe, X-QGeN, where Ge is about 0.5 at. % to about 50 at. % and nitrogen is less than about 20 at. %), where X is one of Co, Ni, Ru, Rh, or Ir, and Q is one of Al or Fe, and combinations thereof. The material of the interlayer 312 may be crystalline. The interlayer has a thickness in the y-direction of about 3 A to about 20 A. The FM layer 314 comprises CoB, CoFeB, CoFeBN, NiFe, CoFeNiN, CoFeN, CoFeHf, or other suitable ferromagnetic materials or alloys. The cap layer 316 can be multiple layers and comprises a resistance material selected from the group consisting of: (1 ) lrxHfyAlz or lrxZryAlz, where x is between about 40 at. % to about 90 at. %, y is about 0.5 at. % to about 60 at. %, and z is about 0.5 at. % to about 60 at. %; (2) ZrQX or HfQX, where X and Q are each individually selected from the group consisting of: Ru, Co, Cu, Ir, Pt, Al, Ti, Nb, Ni, RuAI, NiFe, and CoFe; (3) SixAh-xN, TixAh-xN, CrxAh-xN, and ZrxAh-xN, where x is a numeral between 0.005 and 1 ; and (4) nitrides of Si, Al, Ti, Cr, and Zr, or any alloy nitride composite combination thereof. The nitrogen content can be stoichiometric but is not required to be stoichiometric.

[0040] Figures 4A-4D illustrate various multilayer buffer layers 304a, 304b, 304c, 304d, according to various embodiments. Each buffer layer 304a-304c may individually be the buffer layer 304 of Figures 3A-3B. The layers of each buffer layer 304a-304d promote a (111) texture for the YPtBi layer 310. When materials are written in the form of “X-Q”, the dash (-) indicates the material is an alloy.

[0041] The buffer layer 304a of Figure 4A comprises an amorphous oxide or nitride layer 420, an amorphous metal layer 422 disposed on the amorphous oxide or nitride layer, a textured pre-seed layer 424 disposed on the amorphous metal layer 422, and a (002) hexagonal or (111) fee layer 426 disposed on theDocket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOtextured pre-seed layer 424. The TSM layer 310 comprising (111 ) YPtBi is disposed on the (002) hexagonal or (111 ) fee layer 426.

[0042] The amorphous oxide or nitride layer 420 may comprise alumina and has a thickness in the y-direction of about 10 A to about 40 A. The amorphous metal layer 422 may comprise NiFeTa, CoFeTaN, NiFeTaN, or CoFeTa and has a thickness in the y-direction of about 10 A to about 40 A. The textured pre-seed layer 424 may comprise Ru and has a thickness in the y-direction of about 4 A to about 6 A. The textured pre-seed layer 424 has a (002) orientation. The (002) hexagonal or (111) fee layer 426 comprises a material selected from the group consisting of: Fe2Mo, Fe2W, Fe2Ti, Fe2(TaW), Co2(NbAI), C02(TaAI), Co2Ti, Co2Ta, Co(Fe2Ta), Co2Nb, NiFeTa, CosZr, NisZr, NisHf, (CuNQsZr, AuScSn, BiCoZr, BiGdPt, BiDyPt, BiNiDy, and BiNiY. In some embodiments, the (002) hexagonal or (111) fee layer 426 comprises a material selected from the group consisting of: Fe2X, where X is one of Ti, Mo, Ta, or TazWi-z, (where z is a numeral between 0.005 and 1), C02X alloys, where X is one of Ti, Nb, Ta, TaAl, or NbAI, and (CoFe)2Ta. A number of the C02X alloys exist both as hexagonal and fee phases. The (111 ) fee materials of the (002) hexagonal or (111 ) fee layer 426 have a-axis lattice parameters in the range of about 6.6 A to about 6.8 A where (cF24 - space group Fd-3m) materials are selected from the group consisting of: C02X, where X is one of Ti, Nb, Ta, Hf, or Zr, (cF24 - space group F-43m materials), NisHf, and XsZr alloys, where X is one of Co, Ni, NiFe, or CuNi. There are also fee (111) ternary alloys (cF12 - space group F-43m) having a-axis lattice parameters in the range of about 6.4 A to 6.7 A that can used as buffer layers, such as AuScSn, BiCoZr, BiNiY, BiNiQ, or Bi-XQ alloys, where X is one of Ni, Pt, and Q is a rare earth, such as Gd and Dy.

[0043] The (002) texture of the textured pre-seed layer 424 provides either a (002) or (111 ) texture to the (002) hexagonal or (111 ) fee layer 426, allowing the (002) hexagonal or (111 ) fee layer 426 to have a (002) or (111 ) orientation. TheDocket No: WESD / 0985USL (WDA-7822-WO)PCT-Application_WDA-7822-WO(002) or (111 ) orientation of the (002) hexagonal or (111 ) fee layer 426 promotes the YPtiBi layer 310 to have a (111) orientation. The textured pre-seed layer 424 comprising Ru has an ahep value of about 2.71 A, and the (002) hexagonal or (111 ) fee layer 426 an ahep value of about 4.65 A to about 4.85 A. The YPtBi layer 310 has an ahep value of about 4.70 A. Thus, the ahep values of the textured pre-seed layer 424 and the (002) hexagonal or (111 ) fee layer 426 closely match that of the YPtBi layer 310, enabling the YPtBi layer 310 to have a (111 ) orientation.

[0044] The buffer layer 304b of Figure 4B comprises the amorphous oxide or nitride layer 420, the amorphous metal layer 422 disposed on the amorphous oxide or nitride layer, the textured pre-seed layer 424 disposed on the amorphous metal layer 422, and a bcc or B2 (111) alloy layer 430 disposed on the textured pre-seed layer 424. The TSM layer 310 comprising (111 ) YPtBi is disposed on the bcc or B2 (111) alloy layer 430. The bcc or B2 (111) alloy layer has an a-axis lattice parameter of about 3.1 A to about 3.4 A. The bcc or B2 (111 ) alloy layer 430 comprises a material selected from the group consisting of: MgAu, Sc-X, where X is one of Al, Ni, Pd, or Au, Ti-X, where X is one of Ru, RuTi, Rh, Pd, Pt, or Au, Ru-X, where X is one of Ti or Ta, TaxWi-x(where x is a numeral between 0.005 and 1 ), Ir-X, where X is one of Sc, Ti, Y, or Zr, Hf-X, where X is one of Co, Ni, Ru, or Pt, Zr-X, where X is one of Co, Cu, Rh, Ru, or Os, and B2-alloy ternaries including (AIMo).5Ti, (AIV).5Ru, (AIZr).5Ru, (HfTi).5Ru, (Co4Ni).2Zr, (Co4Fe).2Zr, and (NbZr3).25Co. The material of the bcc or B2 (111) alloy layer 430 may be ordered BCC or disordered BCC if the material is crystalline. The bcc or B2 (111 ) alloy layer 430 has a thickness in the y-direction of about 5 A to about 40 A.

[0045] The (111) orientation of the B2 alloy (111) layer 430 promotes the YPtiBi layer 310 to have a (111) orientation. The textured pre-seed layer 424 comprising Ru has an ahep value of about 2.71 A, and the B2 alloy (111) layerDocket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WO430 an ahcp value of about 4.32 A to about 4.75 A. The YPtBi layer 310 has an ahcp value of about 4.70 A. Thus, the ahcp values of the textured pre-seed layer 424 and the B2 alloy (111 ) layer 430 closely match that of the YPtBi layer 310, enabling the YPtBi layer 310 to have a (111 ) orientation.

[0046] The buffer layer 304c of Figure 4C comprises the amorphous oxide or nitride layer 420, the amorphous metal layer 422 disposed on the amorphous oxide or nitride layer, the textured pre-seed layer 424 disposed on the amorphous metal layer 422, a first bcc or B2 layer 432 disposed on the textured pre-seed layer 424, and a second bcc or B2 layer 434 disposed on the first bcc or B2 layer 432. The TSM layer 310 comprising (111 ) YPtBi is disposed on the second bcc or B2 layer 434. The first and second bcc or B2 layers 432, 434 each has a (111 ) orientation. The (111 ) orientation of the first and second bcc or B2 layers 432, 434 promotes the YPtiBi layer 310 to have a (111) orientation. The first bcc or B2 layer 432 has a thickness in the y-direction of about 5 A to about 40 A, and the second bcc or B2 layer 434 has a thickness in they-direction of about 5 A to about 40 A.

[0047] The first bcc or B2 layer 432 comprises a material having an ahcp value closer to that of the textured pre-seed layer 424, and the second bcc or B2 layer 434 comprises a material having an ahcp value closer to that of the TSM layer 310. For example, the first bcc or B2 layer 432 has an ahcp value between about 4.34 A to about 4.54 A, and the second bcc or B2 layer 434 has an ahcp value between about 4.55 A to about 4.75 A. The first bcc or B2 layer 432 having slightly lower a-axis lattice parameter comprises a material selected from the group consisting of: RuTi, RhTi, (HfTi).5Ru, (Co4Ni).2Zr, and (Co4Fe).2Zr. The second BCC or B2 layer 434 having slightly higher a-axis lattice parameter comprises a material selected from the group consisting of: Zr-X, where X is one of Co, Cu, Ru, Rh, or Os, Ir-X, where X is one of Sc, Y, or Zr, and TaxWi-x(whereDocket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOx is a numeral between 0.005 and 1). The first and second bcc or B2 alloy layers 432, 434 comprise different materials.

[0048] The buffer layer 304d of Figure 4D comprises a first portion 304di comprising the amorphous oxide or nitride layer 420, and the amorphous metal layer 422 disposed on the amorphous oxide or nitride layer, the FM layer 314 disposed on the first portion 304di, and a second portion 304d2 disposed on the FM layer 314, the second portion 304d2 comprising a polarization layer 436, the pre-seed layer 424 disposed on the polarization layer 436, and a bcc or B2 (111 ) layer 438 disposed on the pre-seed layer 424. The TSM layer 310 is disposed on the second portion 304d2.

[0049] The polarization layer 436 is optional and may comprise MgO and has a thickness in the y-direction of about 3 A to about 5 A to effect the pre-seed layer 424 texture. The bcc or B2 (111) alloy layer 438 has an a-axis lattice parameter of about 3.1 A to about 3.4 A. The bcc or B2 (111 ) alloy layer 438 comprises a material selected from the group consisting of: MgAu, Sc-X, where X is one of Al, Ni, Pd, or Au, Ti-X, where X is one of Ru, RuTi, Rh, Pd, Pt, or Au, Ru-X, where X is one of Ti or Ta, TaxWi-x(where x is a numeral between 0.005 and 1 ), Ir-X, where X is one of Sc, Ti, Y, or Zr, Hf-X, where X is one of Co, Ni, Ru, or Pt, Zr-X, where X is one of Co, Cu, Rh, Ru, or Os, and B2-alloy ternaries including (AIMo).sTi, (AIV).5Ru, (AIZr).5Ru, (HfTi).5Ru, (Co4Ni).2Zr, (Co4Fe).2Zr, and (NbZr3).25Co. The material of the bcc or B2 (111 ) alloy layer 438 may be ordered BCC (B2) or disordered BCC (A2) if the material is crystalline. The bcc or B2 alloy layer 438 has a thickness in the y-direction of about 10 A to about 15 A. In such an embodiment, the FM layer 314 may comprise an amorphous material selected from the group consisting of: CoNbHf, CoB, CoFeB, CoFeBN, NiFeB, CoFeNiN, CoFeN, CoFeHfB, CoFeTaB, NiFeTaB, NiFeHfB, and other suitable amorphous ferromagnetic materials or alloys. Nitrogen can be added to all amorphous FM layers 314 in a low amount in certain embodiments.Docket No: WESD / 0985USL (WDA-7822-WO)PCT-Application_WDA-7822-WO

[0050] Thus, each buffer layer 304a-304d promotes a (111) orientation in the TSM layer 310 while further functioning as a migration and shunt barriers for the spintronic stacks 300, 350. Further, the buffer layers 304a-304d have no negative chemical interactions with the TSM layer 310.

[0051] Figure 5A is a schematic cross-sectional view of a SOT device 500 for use in a MAMR magnetic recording head, such as the MAMR magnetic recording head of the drive 100 of Figure 1 or other suitable magnetic media drives. The SOT device 500 comprises a SOT layer 310 orientation formed over a buffer layer 304 formed over a substrate 501 , such as the SOT layer 310 and the buffer layer 304 of Figure 3A-3B. Thus, the SOT layer 310 may comprise YPtBi having a (111 ) orientation. A spin torque layer (STL) 570 is formed over the SOT layer 310. The STL 570 comprises a ferromagnetic material such as one or more layers of CoFe, Coir, NiFe, and CoFeX alloy wherein X = B, Ta, Re, or Ir. The STL 570 may correspond to the FM layer 314 of the earlier figures.

[0052] In certain embodiments, an electrical current shunt block layer 560 is disposed between the SOT layer 310 and the STL 570. The electrical current shunt blocking layer 560 reduces electrical current from flowing from the SOT layer 310 to the STL 570 but allows spin orbital coupling of the SOT layer 310 and the STL 570. In certain embodiments, the electrical current shunt blocking layer 560 comprises a magnetic material that provides greater spin orbital coupling between the SOT layer 310 and the STL 570 than a nonmagnetic material. In certain embodiments, the electrical current shunt blocking layer 560 comprises a magnetic material of FeCo, FeCoM, FeCoMO, FeCoMMeO, FeCoM / MeO stack, FeCoMNiMnMgZnFeO, FeCoM / NiMnMgZnFeO stack, multiple layers / stacks thereof, or combinations thereof in which M is one or more of B, Si, P, Al, Hf, Zr, Nb, Ti, Ta, Mo, Mg, Y, Cu, Cr, and Ni. Me is one or more of Si, Al, Hf, Zr, Nb, Ti, Ta, Mg, Y, or Cr. In certain embodiments, the electrical current shunt blocking layer 560 is formed to a thickness from about 10 A toDocket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOabout 100 A. In certain aspects, an electrical current shunt blocking layer 560 with a thickness of over 100 A may reduce the spin-orbital coupling of the SOT layer 310 and the STL 570. In certain aspects, an electrical current shunt blocking layer having a thickness of less than 10 A may not sufficiently reduce electrical current from SOT layer 310 to the STL 570.

[0053] In certain embodiments, additional layers are formed over the STL 570 such as a spacer layer 580 and a pinning layer 590. The pinning layer 590 can partially pin the STL 570. The pinning layer 590 comprises a single or multiple layers of PtMn, NiMn, IrMn, IrMnCr, CrMnPt, FeMn, other antiferromagnetic materials, or combinations thereof. The spacer layer 580 comprises single or multiple layers of magnesium oxide, aluminum oxide, other nonmagnetic materials, or combinations thereof.

[0054] Figures 5B-5C are schematic MFS views of certain embodiments of a portion of a MAMR magnetic recording head 210 with a SOT device 500 of Figure 5A. The MAMR magnetic recording head 210 can be the magnetic recording head Figure 2 or other suitable magnetic recording heads in the drive 100 of Figure 1 or other suitable magnetic media drives such as tape drives. The MAMR magnetic recording head 210 includes a main pole 220 and a trailing shield 240 in a track direction. The SOT device 500 is disposed in a gap between the main pole and the trailing shield 240.

[0055] During operation, charge current through a SOT layer 310 acting as a spin Hall layer generates a spin current in the YPtBi layer. The spin orbital coupling of the YPtBi layer and a spin torque layer (STL) 570 causes switching or precession of magnetization of the STL 570 by the spin orbital coupling of the spin current from the SOT layer 310. Switching or precession of the magnetization of the STL 570 can generate an assisting AC field to the write field. Energy-assisted magnetic recording heads based on SOT have multiple times greater power efficiency than MAMR magnetic recording heads based on Docket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOspin transfer torque. As shown in Figure 5B, an easy axis of a magnetization direction of the STL 570 is perpendicular to the MFS from shape anisotropy of the STL 570, from the pinning layer 590 of Figure 5A, and / or from hard bias elements proximate to the STL 570. As shown in Figure 5C, an easy axis of a magnetization direction of the STL 570 is parallel to the MFS from shape anisotropy of the STL 570, from the pinning layer 590 of Figure 5A, and / or from complex bias elements proximate to the STL 570.

[0056] Figure 6 is a schematic cross-sectional view of an SOT MTJ 601 used as a MRAM device 600. The MRAM device 600 comprises a reference layer (RL) 610, a spacer layer 620 over the RL 610, a recording layer 630 over the spacer layer 620, a buffer layer 304 over an electrical current shunt block layer 640 over the recording layer 630, and a SOT layer 310 over the buffer layer 304. The SOT layer 310 and the buffer layer 304 may be the SOT layer 310 and the buffer layer 304 of Figures 3A-3B. The RL 610 may be the FM layer 314 of those figures. Thus, the SOT layer 310 may comprise YPtBi having a (111) orientation.

[0057] The RL 610 comprises single or multiple layers of CoFe, other ferromagnetic materials, and combinations thereof. The spacer layer 620 comprises single or multiple layers of magnesium oxide, aluminum oxide, other dielectric materials, or combinations thereof. The recording layer 630 comprises single or multiple layers of CoFe, NiFe, other ferromagnetic materials, or combinations thereof.

[0058] As noted above, in certain embodiments, the electrical current shunt block layer 640 is disposed between the buffer layer 304 and the recording layer 630. The electrical current shunt blocking layer 640 reduces electrical current from flowing from the SOT layer 310 to the recording layer 630. The electrical current shunt blocking layer 640 still allows spin orbital coupling of the SOT layer 310 and the recording layer 630. For example, writing to the MRAM device can be enabled by the spin orbital coupling of the TSM layer and the recording layer Docket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WO630, which allows switching of magnetization of the recording layer 630 by the spin orbital coupling of the spin current from the SOT layer 310. In certain embodiments, the electrical current shunt blocking layer 640 comprises a magnetic material that provides greater spin orbital coupling between the SOT layer 310 and the recording layer 630 than a nonmagnetic material. In certain embodiments, the electrical current shunt blocking layer 640 comprises a magnetic material of FeCoM, FeCoMO, FeCoMMeO, FeCoM / MeO stack, FeCoMNiMnMgZnFeO, FeCoM / NiMnMgZnFeO stack, multiple layers / stacks thereof, or combinations thereof, in which 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.

[0059] The MRAM device 600 of Figure 6 may include other layers, such as pinning layers, pinning structures (e.g., a synthetic antiferromagnetic (SAF) pinned structure), electrodes, gates, and other structures. Other MRAM devices besides the structure of Figure 6 can be formed utilizing a SOT layer 310 over a buffer layer 304 to form a SOT MTJ 601 .

[0060] Figure 7 illustrates a schematic of a simplified deep neural network (DNN) or logic cell 700, according to one embodiment. The DNN 700 comprises a plurality of cells or neural nodes 702a, 702b, 702c, 702d, 702e (collectively referred to herein as neural nodes 702). Each neural node 702 comprises a plurality of spin orbital-spin orbital (SO-SO) cells, where each SO-SO cell is a three-terminal device, comprising a control or weight, an input, and an output. Each SO-SO cell may comprise one or more of the spintronic stacks 300a-300d of Figures 3A-3B. An input current (input 1 , input 2, input n) is applied to a first input layer (i) of neural nodes 702a and multiplied by the control or weight.

[0061] The output of each neural node 702a of the input layer is then output to each neural node 702b in a first hidden layer (hi ) of the DNN 700 as the input for each neural node 702b, where each received input at each neural node 702b is Docket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOthen multiplied by a respective weight for the respective input of each neural node 702b. A weight may conceptually represent a strength of the connection between a neural node in one layer (e.g., neural node 702a) and another neural node in the next layer (e.g., neural node 702b). The results of the multiplications are collectively summed together and sent to a non-linear activation function (not shown here), such as a step or a rectified linear unit (ReLU) function, which determines the final output for that neural node 702b. This multiplication, summation and activation function sequence of processes is then repeated in the various layers h2, h3, etc. throughout the DNN. While three hidden layers are shown, the DNN 700 may comprise any number of hidden layers. Finally, the output of the last hidden layer (here, the third hidden layer) is output to output neural nodes 702e of an output layer (o) as a final result.

[0062] Figure 8 illustrates a spin orbital-spin orbital (SO-SO) device 800, according to one embodiment. The SO-SO device 800 may be utilized within the DNN 700 of Figure 7, such as a SO-SO cell. The various layers of the SO-SO device 800 are not drawn to scale, and are intended for illustrative purposes only. The SO-SO devices may be referred to herein as SOT devices. A plurality of SO-SO devices 800 may be configured to function as a neural node 102 of Figure 7. Thus, a collection of SO-SO devices may be configured to represent a layer (i, hi , h2, h3, o) of the DNN of Figure 7.

[0063] In some embodiments, the SO-SO device 800 comprises a seed layer 802, a first spin orbit torque (SOT) layer 310-1 (SOT1 ) disposed on the seed layer 802, a first interlayer 312-1 disposed on the first SOT layer 310-1 , a ferromagnetic (FM) layer 314 disposed on the first interlayer 312-1 , an oxide layer 810 (e.g., an MgO layer) disposed on the FM layer 314, a second interlayer 312-2 disposed on the oxide layer 810, a second SOT layer 310-2 (SOT2) disposed on the second interlayer 312-2, a buffer layer 304 disposed on the second SOT layer 310-2, and a cap layer 818 disposed on the buffer layer 304.Docket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOThe oxide layer 810 may comprise other materials, such as oxides of Ti, V, Cr, Mn, Fe, Ni, Zr, nitrides of Sc, Ti, V, Cr, Fe, Zr, Ta, Hf, W, carbides of Sc, Ti, V, Zr, Ta, Hf, W, and alloy combinations thereof.

[0064] The first and second interlayers 312-1 , 312-2 may each individually be the interlayer 312 of Figures 3-4. The buffer layer 304 may be the buffer layer 304 of Figures 3-4. The SOT1 310-1 and the SOT2 310-2 may each individually be the SOT layer 310 of Figures 3-4. The FM layer 314 may be the FM layer 314 of Figures 3-4.

[0065] In some embodiments, the SO-SO device 800 comprises three terminals or interconnects. The first SOT layer 310-1 is coupled to an interconnect or terminal 1. The second SOT layer 310-2 is coupled to an interconnect or terminal 3, where the interconnect or terminal 3 is coupled to the first SOT layer 310-1 of a second SO-SO device via terminal 1. An input current is applied to terminal 2 (representing an input Xncurrent to a neural node) and it flows out-of-plan (current-perpendicular-to-plane (CPP)) through the whole stack toward the seed layer 802. The arrows associated with the terminals indicate the direction of current flows, according to some embodiments. The interconnects or terminals serves as connection points for joining two or more SO-SO devices. Thus, multiple SO-SO devices 800 can be arranged to build out various circuits.

[0066] Therefore, by utilizing a buffer layer having a hexagonal (002) or fee (111 ) orientation in a spintronic stack, the TSM layer is able to grow in a (111 ) orientation. Furthermore, such buffer layers comprising the above-mentioned materials function as migration and shunt barriers for the spintronic stacks, and have no negative chemical interactions with the TSM layer.

[0067] In one embodiment, a spintronic stack comprises a YPtBi layer having a (111 ) orientation, a ferromagnetic layer, and a buffer layer, the buffer layerDocket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOcomprising: an amorphous oxide or nitride layer, an amorphous metal layer disposed on the amorphous oxide or nitride layer, a textured pre-seed layer disposed on the amorphous metal layer, and a (002) hexagonal or (111 ) fee layer disposed on the textured pre-seed layer, the (002) hexagonal or (111 ) fee layer having a-axis lattice parameters around 4.6 A to 4.8 A when the (002) hexagonal or (111 ) fee layer has a (002) hexagonal orientation, the (002) hexagonal or (111 ) fee layer having a (002) hexagonal orientation comprising an alloy material selected from the group consisting of: Fe2X, where X is one of Ti, Mo, Ta, or TazWi-z, (where z is a numeral between 0.005 and 1 ), C02X alloys, where X is one of Ti, Nb, Ta, TaAl, or NbAI, and (CoFe)2Ta. The (111 ) fee materials of the (002) hexagonal or (111 ) fee layer have a-axis lattice parameters in the range of about 6.6 A to about 6.8 A where (cF24 - space group Fd-3m) materials are selected from the group consisting of: C02X, where X is one of Ti, Nb, Ta, Hf, or Zr, (cF24 - space group F-43m materials), NisHf, and XsZr alloys, where X is one of Co, Ni, NiFe, or CuNi. There are also fee (111 ) ternary alloys (cF12 - space group F-43m) having a-axis lattice parameters in the range of about 6.4 A to 6.7 A that can used as buffer layers, such as AuScSn, BiCoZr, BiNiY, or Bi-XQ alloys, where X is one of Ni, Pt, and Q is a rare earth, such as Gd and Dy.

[0068] The textured pre-seed layer comprises Ru, wherein the amorphous oxide or nitride layer comprises alumina, and wherein the amorphous metal layer comprises NiFeTa or CoFeTaN. The YPtBi layer is disposed between the buffer layer and the ferromagnetic layer. The ferromagnetic layer is disposed between the buffer layer and the YPtBi layer. The (002) hexagonal or (111 ) fee layer has a thickness of about 5 A to about 40 A. A memory cell comprises the spintronic stack. A logic cell comprises the spintronic stack. A magnetic sensor comprises the spintronic stack.

[0069] In another embodiment, a spintronic stack comprises a YPtBi layer having a (111 ) orientation, a ferromagnetic layer, and a buffer layer, the bufferDocket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOlayer comprising: an amorphous oxide or nitride layer, an amorphous metal layer disposed on the amorphous oxide or nitride layer, a textured pre-seed layer disposed on the amorphous metal layer, and a bcc or B2 alloy layer disposed on the textured pre-seed layer, the bcc or B2 alloy layer having an a-axis lattice parameter of about 3.1 A to about 3.4 A, the bcc or B2 alloy layer comprising a material selected from the group consisting of: MgAu, Sc-X, where X is one of Al, Ni, Pd, or Au, Ti-X, where X is one of Ru, RuTi, Rh, Pd, Pt, or Au, Ru-X where X is one of Ti or Ta, TaxWi-x(where x is a numeral between 0.005 and 1 ), Ir-X, where X is one of Sc, Ti, Y, or Zr, Hf-X, where X is one of Co, Ni, Ru, Pt, Zr-X, where X is one of Co, Cu, Rh, Ru, and Os, and B2-alloy ternaries including (AIMo).5Ti, (AIV).sRu, (AIZr).sRu, (HfTi).5Ru, (Co4Ni).2Zr, (Co4Fe).2Zr, and (NbZr3).25Co.

[0070] The B2 alloy layer has a (111 ) orientation. The textured pre-seed layer comprises Ru having a (002) orientation. The YPtBi layer is disposed between the buffer layer and the ferromagnetic layer. The ferromagnetic layer is disposed between the buffer layer and the YPtBi layer. A memory cell comprises the spintronic stack. A logic cell comprises the spintronic stack. A magnetic sensor comprises the spintronic stack.

[0071] In yet another embodiment, a spintronic stack comprises a YPtBi layer having a (111 ) orientation, a ferromagnetic layer, and a buffer layer, the buffer layer comprising: an amorphous oxide or nitride layer, an amorphous metal layer disposed on the amorphous oxide or nitride layer, a textured pre-seed layer disposed on the amorphous metal layer, a first bcc or B2 alloy layer disposed on the textured pre-seed layer, the first bcc or B2 alloy layer comprising a material selected from the group consisting of: RuTi, RhTi, (HfT .sRu, (Co4Ni)2Zr, and (Co4Fe)2Zr, and a second bcc or B2 alloy layer disposed on the first bcc or B2 alloy layer, the second bcc or B2 alloy layer comprising a material selected from the group consisting of: Zr-X, where X is one of Co, Cu, Ru, Rh, or Os, Ir-X,Docket No: WESD / 0985USL (WDA-7822-WO) PCT-Application_WDA-7822-WOwhere X is one of Sc, Y, or Zr, and TaxWi-x(where x is a numeral between 0.005 and 1 ).

[0072] The first bcc layer has a lower ahcp value than the second bcc layer. The first bcc layer has a thickness of about 5 A to about 40 A, and wherein the second bcc layer has a thickness of about 5 A to about 40 A. A memory cell comprises the spintronic stack. A logic cell comprises the spintronic stack. A magnetic sensor comprises the spintronic stack.

[0073] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.Docket No: WESD / 0985USL (WDA-7822-WO)PCT-Application_WDA-7822-WO

Claims

WHAT IS CLAIMED IS:1 . A spintronic stack, comprising: a YPtBi layer having a ( 111 ) orientation; a ferromagnetic layer; and a buffer layer, the buffer layer comprising: an amorphous oxide or nitride layer; an amorphous metal layer disposed on the amorphous oxide or nitride layer; a textured pre-seed layer disposed on the amorphous metal layer; and a (002) hexagonal or (111 ) fee layer disposed on the pre-seed layer, the (002) hexagonal or (111) fee layer comprising a material selected from the group consisting of:Fe2X, where X is one of Ti, Mo, Ta, or TazWi-z, where z is a numeral between 0.005 and 1 ,C02X alloys, where X is one of Ti, Nb, Ta, TaAl, or NbAI,(CoFe)2Ta,C02X, where X is one of Ti, Nb, Ta, Hf, or Zr,NisHf, andXsZr alloys, where X is one of Co, Ni, NiFe, or CuNi,AuScSn,BiCoZr,BiNiY, andBi-XQ alloys, where X is one of Ni or Pt, and Q is Gd or Dy.

2. The spintronic stack of claim 1 , wherein the textured pre-seed layer comprises Ru, wherein the amorphous oxide or nitride layer comprises alumina,Docket No: WESD / 0985USL (WDA-7822-WO)PCT-Application_WDA-7822-WOand wherein the amorphous metal layer comprises NiFeTa, CoFeTaN, NiFeTaN, or CoFeTa.

3. The spintronic stack of claim 1 , wherein the YPtBi layer is disposed between the buffer layer and the ferromagnetic layer.

4. The spintronic stack of claim 1 , wherein the ferromagnetic layer is disposed between the buffer layer and the YPtBi layer.

5. The spintronic stack of claim 1 , wherein the (002) hexagonal or (111 ) fee layer has a thickness of about 5 A to about 40 A.

6. A memory cell comprising the spintronic stack of claim 1.

7. A logic cell comprising the spintronic stack of claim 1 .

8. A magnetic sensor comprising the spintronic stack of claim 1 .

9. A magnetic recording device comprising the spintronic stack of claim 1 .

10. A spintronic stack, comprising: a YPtBi layer having a (111 ) orientation; a ferromagnetic layer; and a buffer layer, the buffer layer comprising: an amorphous oxide or nitride layer; an amorphous metal layer disposed on the amorphous oxide or nitride layer; a textured pre-seed layer disposed on the amorphous metal layer; andDocket No: WESD / 0985USL (WDA-7822-WO)PCT-Application_WDA-7822-WOa bcc or B2 alloy layer disposed on the textured pre-seed layer, the bcc or B2 alloy layer comprising a material selected from the group consisting of:MgAu,Sc-X, where X is one of Al, Ni, Pd, or Au,Ti-X, where X is one of Ru, RuTi, Rh, Pd, Pt, or Au,Ru-X where X is one of Ti or Ta,TaxWi-x (where x is a numeral between 0.005 and 1 ), Ir-X, where X is one of Sc, Ti, Y, or Zr,Hf-X, where X is one of Co, Ni, Ru, or Pt,Zr-X, where X is one of Co, Cu, Rh, Ru, or Os,(AIMo).sTi,(AIV).sRu,(AIZr).sRu,(HfTi).sRu,(Co4Ni).2Zr,(Co4Fe)2Zr, and(NbZr3).25Co.

11. The spintronic stack of claim 10, wherein the bcc or B2 alloy layer has a (111 ) orientation.

12. The spintronic stack of claim 10, wherein the textured pre-seed layer comprises Ru having a (002) orientation.

13. The spintronic stack of claim 10, wherein the YPtBi layer is disposed between the buffer layer and the ferromagnetic layer.Docket No: WESD / 0985USL (WDA-7822-WO)PCT-Application_WDA-7822-WO14. The spintronic stack of claim 10, wherein the ferromagnetic layer is disposed between the buffer layer and the YPtBi layer.

15. A memory cell comprising the spintronic stack of claim 10.

16. A logic cell comprising the spintronic stack of claim 10.

17. A magnetic sensor comprising the spintronic stack of claim 10.

18. A magnetic recording device comprising the spintronic stack of claim 10.

19. A spintronic stack, comprising: a YPtBi layer having a (111 ) orientation; a ferromagnetic layer; and a buffer layer, the buffer layer comprising: an amorphous oxide or nitride layer; an amorphous metal layer disposed on the amorphous oxide or nitride layer; a textured pre-seed layer disposed on the amorphous metal layer; a first bcc or B2 alloy layer disposed on the textured pre-seed layer; and a second bcc or B2 alloy layer disposed on the first bcc or B2 alloy layer, the first and second bcc or B2 alloy layers each individually comprising a material selected from the group consisting of:MgAu,Sc-X, where X is one of Al, Ni, Pd, or Au,Ti-X, where X is one of Ru, RuTi, Rh, Pd, Pt, or Au,Ru-X where X is one of Ti or Ta,Docket No: WESD / 0985USL (WDA-7822-WO)PCT-Application_WDA-7822-WOTaxWi-x (where x is a numeral between 0.005 and 1 ),Ir-X, where X is one of Sc, Ti, Y, or Zr,Hf-X, where X is one of Co, Ni, Ru, or Pt,Zr-X, where X is one of Co, Cu, Rh, Ru, or Os,(AIMo).5Ti,(AIV).5RU,(AIZr).sRu,(HfTi).sRu,(Co4Ni).2Zr,(Co4Fe).2Zr, and(NbZr3).25Co, wherein the first and second bcc or B2 alloy layers comprise different materials.

20. The spintronic stack of claim 19, wherein the first bcc or B2 alloy layer has a lower ahcp value than the second bcc layer.21 . The spintronic stack of claim 19, wherein the first bcc or B2 alloy layer has a thickness of about 5 A to about 40 A, and wherein the second bcc or B2 alloy layer has a thickness of about 5 A to about 40 A.

22. A memory cell comprising the spintronic stack of claim 19.

23. A logic cell comprising the spintronic stack of claim 19.

24. A magnetic sensor comprising the spintronic stack of claim 19.

25. A magnetic recording device comprising the spintronic stack of claim 19.Docket No: WESD / 0985USL (WDA-7822-WO)PCT-Application_WDA-7822-WO

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