Patent Application
20240240994
Embodiments of the present disclosure generally relate to a spin-orbit torque (SOT) layered device for measuring temperature based on the spin Seebeck effect and the associated inverse spin Hall effect.
At the heart of a computer is a magnetic disk drive. Information is written to and read from a disk as it rotates past read and write heads that are positioned very closely to the magnetic surface of the disk. Fly-height is the spacing between the read and write heads and the recording disk. A key variable in fly-height is the read/write element protrusion towards the recording disk. When data is written to the disk, a high frequency electrical current is applied to the head's write coil. With the applied write current, the write element heats up and expands, generating additional protrusion of the read/write element region of the head towards the disk. This thermally-driven protrusion phenomena reduces the accurate spacing control between the read/write elements on the head and may result in destructive head/disk interactions. Furthermore, in various forms of energy assisted magnetic recording such as heat assisted magnetic recording (HAMR) and microwave assisted magnetic recording (MAMR), the injection of the assistive energy to aid recording can also cause head expansion and protrusion toward the disk. Additionally, the fly-height may be controlled by a controlled heating element called a thermal fly-height control (TFC) to intentionally induce expansion of the recording head to reduce the spacing between the head and disk.
As demand for higher capacity storage devices continues to increase, issues regarding thermal fly-height control (TFC) efficiency and head protrusion in hard disk drive (HDD) recording head environments become more important. Since head temperature monitoring is critical to both, there is a need for an improved temperature detection device.
The present disclosure generally relates to temperature detection devices, comprising an antiferromagnetic (AFM) layer, a ferromagnetic (FM) layer disposed on the AFM layer, and a spin-orbit torque (SOT) material layer disposed on the FM layer. The SOT material layer may comprise: a SOT material portion; a SOT material portion and an insulating material portion; or a plurality of SOT material portions and a plurality of insulating material portions. The temperature detection devices may also have a second FM layer disposed on the SOT material layer. The temperature detection devices may also have a second AFM layer disposed on the second FM layer. In another embodiment, the temperature detection devices may also have a heat sink.
In one embodiment, a temperature detection device comprises a temperature detection stack, comprising: a first antiferromagnetic (AFM) layer, a first ferromagnetic (FM) layer disposed on the first AFM layer; a spin-orbit torque (SOT) material layer disposed on the first FM layer, wherein the SOT material layer further comprises a SOT material layer portion, a second FM layer disposed on the SOT material layer, and a second AFM layer disposed on the second FM layer.
In another embodiment, a temperature detection device, comprises a spin-orbit torque (SOT) portion having a surface at a media facing surface (MFS), a heat sink portion disposed adjacent the SOT portion, a first ferromagnetic (FM) portion disposed adjacent to the SOT portion and the heat sink portion, wherein the FM portion has a surface at the MFS, a second FM portion disposed adjacent to the SOT portion and opposite the FM portion, wherein the second FM portion has a surface at the MFS, an first antiferromagnetic (AFM) portion spaced from the SOT portion and disposed adjacent the FM portion and the heat sink portion, wherein the AFM portion has a surface disposed at the MFS, and a second AFM portion spaced from the SOT portion and disposed adjacent the second FM portion and the heat sink portion, wherein the second AFM portion has a surface disposed at the MFS.
In yet another embodiment, a temperature detection device, comprises a spin-orbit torque (SOT) portion having a first surface at a media facing surface (MFS), a second surface opposite the first surface, a third surface connecting the first and second surfaces, and a fourth surface opposite the third surface, wherein the first surface has a first length and the third surface has a second length, and wherein the first length is greater than the second length, a heat sink portion disposed adjacent the SOT portion, a ferromagnetic (FM) portion disposed adjacent to the SOT portion, and an antiferromagnetic (AFM) portion spaced from the SOT portion and disposed adjacent the FM portion and the heat sink portion.
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.
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.
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).
The present disclosure generally relates to temperature detection devices, comprising an antiferromagnetic (AFM) layer, a ferromagnetic (FM) layer disposed on the AFM layer, and a spin-orbit torque (SOT) material layer disposed on the FM layer. The SOT material layer may comprise: a SOT material portion; a SOT material portion and an insulating material portion; or a plurality of SOT material portions and a plurality of insulating material portions. The temperature detection devices may also have a second FM layer disposed on the SOT material layer. The temperature detection devices may also have a second AFM layer disposed on the second FM layer. In another embodiment, the temperature detection devices may also have a heat sink.
In one embodiment, a temperature detection device may be utilized in a magnetic media disk drive 100, e.g., as part of the recording head. Conventionally, an embedded contact sensor (ECS), a resistive based device, is used as part of a critical function of head flying height and head-media contact regulation. One example implementation is described in co-owned U.S. Pat. No. U.S. Pat. No. 8,873,191B2, “Fly-height control and touchdown detection,” issued Oct. 28, 2014, the disclosure of which is hereby incorporated by reference. The resistance of ECS can be changed by the air bearing cooling and frictional induced heat caused by head-disk contact at the head disk interface. Such resistance can be measured and used by the controller of the magnetic recording device to regulate flying height of the recording head.
The temperature detection device as described herein may be used in lieu of the ECS. Placed at or near the media facing surface (MFS) of the recording head, the temperature detection device can similarly detect the temperature changes caused by the air bearing cooling and frictional induced heat caused by head-media contact at the head disk interface. The temperature detection device in various embodiments includes spin orbit torque materials, and uses the spin Seebeck effect and the associated inverse spin Hall effect to generate a voltage signal output that can be used by the drive controller to regulate recording head flying height and media contact.
Besides fly height and contact regulation, the temperature detection device may also be used to monitor temperature in the recording head. In particular, in various forms of energy assisted magnetic recording such as HAMR and MAMR, the injection of the assistive energy to aid recording can cause heating effects throughout the recording head, and the temperature detection device may be placed, for example, near the writer or an energy generating component such as the near field transducer (NFT) in HAMR to monitor temperature for reliability enhancements.
At least one slider 113 is positioned near the magnetic disk 112, each slider 113 supporting one or more magnetic head assemblies 121 that include a SOT-based temperature detection 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 way of 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
During operation of the disk drive 100, the rotation of the magnetic disk 112 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 counter-balances the slight spring force of suspension 115 and supports slider 113 off and slightly above the disk surface 122 by a small, substantially constant spacing during normal operation.
The various components of the disk drive 100 are controlled in operation by control signals generated by control unit 129, such as access control signals and internal clock signals. Typically, the control unit 129 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 optimally move and position slider 113 to the desired data track on the magnetic disk 112. Write and read signals are communicated to and from write and read heads on the magnetic head assembly 121 by way of recording channel 125.
The above description of a typical magnetic media drive and the accompanying illustration of
In some embodiments, the magnetic read head 211 is a SOT read head that includes an SOT sensing element 204 located between SOT shields S1 and S2. The magnetic fields of the adjacent magnetized regions in the magnetic disk 112 are detectable by the SOT sensing element 204 as the recorded bits. In other embodiments, the magnetic read head 211 includes a magneto-resistive (MR) type sensing element 204 located between the two shields S1 and S2.
The write head 210 includes a main pole 220, a leading shield 206, a trailing shield 240, and a coil 218 that excites the main pole 220. The coil 218 may have a “pancake” structure which winds around a back-contact between the main pole 220 and the trailing shield 240, instead of a “helical” structure shown in
In
In some embodiments, the read head 211 is a spin torque oscillator (STO) read head with an STO sensing element 204 located between shields S1 and S2. The magnetic fields of the adjacent magnetized regions in the magnetic disk 112 are detectable by the STO sensing element 204 as the recorded bits. The STO reader may be operated in a 2-terminal or a 3-terminal configuration, with an in-plane current flowing inside SOT structure while a small sensing current flows perpendicular to the film plane, and the signal is read out by measuring the frequency of magnetic layer precession. The SOT device of various embodiments can be incorporated into the read head 211.
A temperature detection device 300 may be located close to the magnetic read head 211. The temperature detection device 300 may be located at the edge of the MFS 212. In some embodiments, the temperature detection device 300 is located closer to the read head 211. The temperature detection device 300 may be located below S1 or above S2, in the down-track direction (above S2 shown in figure). In other embodiments, the temperature detection device 300 is located closer to the write head 210. The temperature detection device 300 may be located between the leading shield 206 and S2. In another embodiment, the temperature detection device 300 may be located close to the write head 210. In yet another embodiment, the temperature detection device 300 may be located close to both the magnetic read head 211 and the write head 210. In some embodiments, the temperature detection device 300 may be located 50 nm to 500 nm from S2 of the read head 211 or below S1 of the read head 211. In other embodiments, the temperature detection device 300 may be located 50 nm to 500 nm from the write head 210.
In other embodiments, the temperature detection device 300 may be, but is not limited to, uncool infrared/terahertz cameras for smart phones or security. In some embodiments, when the temperature detection device 300 is utilized for infrared applications, an absorber (not shown) that is on the outside of the temperature detection device may be vanadium oxide or amorphous silicon. In some embodiments, when the temperature detection device 300 is utilized for terahertz applications, the absorber may be layers of carbon nanotubes.
In one embodiment, as shown in
In
The FM layer(s) 302, 302a, 302b (described below) is pinned in the transverse direction (y-direction) such that a spin polarization of spin current injected into the SOT material portion 312 is along the y-direction. The signal output is the vector product of the spin current in the z-direction and spin polarization in the y-direction. The signal output is maximized if it is measured along the x-axis across the SOT material portion(s) 312. The output magnitude of the signal is dependent on the geometrical effect of width and thickness of the SOT material portion 312 utilized in any of the temperature detection stacks 303a, 303b, 303c, 303d, 303f. SOT materials with high spin Hall angles increases the overall signal.
The final signal can be calculated with the following equation:
In the above equation, t is the thickness of the SOT material portion 312, W is the width of the SOT material portion 312 in the x-direction, Is is the spin diffusion length of the FM layer(s) 302, Vs is the spin voltage due to the spin Seebeck effect, Vx is the final signal output on the SOT material portion(s) 312, ΔT is the difference in temperature, θ is the spin Hall angle of the SOT material portion, and Sss is the spin Seebeck coefficient of the FM layer(s) 302 and is approximately 1 μV/K for magnetic materials. In one example, the SOT material portion 312 may be BiSb with a width of about 10 μm, a thickness of about 10 nm, and a spin Hall angle of about 20. In this example, the signal output is approximately 5 mv/K.
Although exemplified in
In
The following discussion of dimensions applies to
Each of the SOT material layers 310a, 310b, 310c, 310d, 310f may individually be the same height, as measured along the y-axis, as any of the FM layers 302, 302a, 302b. In other embodiments, each SOT material layer 310a, 310b, 310c, 310d, 310f may have a smaller height than the FM layers 302, 302a, 302b. In yet other embodiments, each SOT material layer 310a, 310b, 310c, 310d, 310f may have a larger height than the FM layers 302, 302a, 302b. In some embodiments, the first FM layer 302a may be the same height as the second FM layer 302b. In other embodiments, the first FM layer 302a may have a smaller or larger height than the second FM layer 302b. In some embodiments, the first AFM layer 301a may be the same height as the second AFM layer 301b. In other embodiments, the first AFM layer 301a may have a smaller or larger height than the second AFM layer 301b. The AFM layers 301, 301a, 301b and the FM layers 302a, 302b may be the same height. The AFM layers 301, 301a, 301b may also have a smaller or larger height than the FM layers 302, 302a, 302b. The height range for each AFM layers 301, 301a, 301b and each FM layers 302, 302a, 302b may individually range from 10 μm to 1 mm. The height of each SOT material portion 312 may individually range from 10 μm to 1 mm.
The SOT material portion(s) 312 and the insulating material portion(s) 311 may have equal heights, as measured along the y-axis. In other embodiments, the SOT material portion(s) 312 may have a longer or shorter height than the insulating material portion(s) 311. The height of the SOT material portion(s) 312 and the insulating material portion(s) 311 may range from 100 nm to 1 μm.
Each SOT material layer 310a, 310b, 310c, 310d, 310f may individually be the same width, as measured along the x-axis, as any FM layers 302, 302a, 302b. In other embodiments, each SOT material layer 310a, 310b, 310c, 310d, 310f may have a shorter width than the FM layers 302, 302a, 302b. In yet other embodiments, each SOT material layer 310a, 310b, 310c, 310d, 310f may have a longer width than the FM layers 302, 302a, 302b. The AFM layers 301, 301a, 301b and the FM layers 302, 302a, 302b may be the same width. The AFM layers 301, 301a, 301b may also have a shorter or longer width than the FM layers 302, 302a, 302b. In some embodiments, the first AFM layer 301a may be the same width as the second AFM layer 301b. In other embodiments, the first AFM layer 301a may have a shorter or longer width than the second AFM layer 301b. In some embodiments, the first FM layer 302a may be the same width as the second FM layer 302b. In other embodiments, the first FM layer 302a may have a shorter or longer width than the second FM layer 302b. The width range for the AFM layers 301, 301a, 301b and the FM layers 302, 302a, 302b may independently range from about 10 μm to about 200 μm. The width of the SOT material layer 310a, 310b, 310c, 310d, 310f may range from 10 μm to 200 μm.
The SOT material portion(s) 312 and the insulating material portion(s) 311 may have equal widths, as measured along the x-axis. In other embodiments, the SOT material portion(s) 312 may have longer or shorter widths than the insulating material portion(s) 311. In embodiments where there are multiple SOT material portions 312, such as in
Each SOT material layer 310a, 310b, 310c, 310d, 310f may individually have the same thickness, as measured along the z-axis, as the FM layers 302, 302a, 302b. In other embodiments, each SOT material layer 310a, 310b, 310c, 310d, 310f may have a smaller thickness than the FM layers 302, 302a, 302b. In yet other embodiments, each SOT material layer 310a, 310b, 310c, 310d, 310f may have a larger thickness than the FM layers 302, 302a, 302b. The AFM layers 301, 301a, 301b and the FM layers 302, 302a, 302b may have the same thickness. The AFM layers 301, 301a, 301b may also have a smaller or larger thickness than the FM layers 302, 302a, 302b. In some embodiments, the first FM layer 302a may be the same thickness as the second FM layer 302b. In other embodiments, the first FM layer 302a may have a smaller or larger thickness than the second FM layer 302b. In some embodiments, the first AFM layer 301a may be the same thickness as the second AFM layer 301b. In other embodiments, the first AFM layer 301a may have a smaller or larger thickness than the second AFM layer 301b. The thickness range for the AFM layers 301, 301a, 301b and the FM layers 302, 302a, 302b may range from 5 nm to 100 nm. The thickness of the SOT material layer 310a, 310b, 310c, 310d, 310f may range from 10 nm to 30 nm.
The heat sink 330 may have the same thickness, as measured along the z-axis, as the temperature detection stack 303a, 303b, 303c, 303d, 303f. In other embodiments, the heat sink 330 may have a larger or smaller thickness than the temperature detection stack 303a, 303b, 303c, 303d, 303f. When the heat sink 330 is smaller than the temperature detection stack 303a, 303b, 303c, 303d, 303f, the heat sink 330 may be located adjacent to one or both of the FM layers 302, 302a, 302b.
The following discussion of materials is applicable to
In some embodiments, the heat sink 330 may be copper (Cu), aluminum (Al), silver (Ag), or any combination thereof.
In some embodiments, the AFM layers 301, 301a, 301b may each individually comprises iridium manganese (IrMn), platinum manganese (PtMn), or other antiferromagnetic materials.
In some embodiments, the FM layers 302, 302a, 302b may each individually comprises one or more of cobalt (Co), iron (Fe), and one or more of boron (B), hafnium (Hf), and/or nickel hafnium (NiHf).
In some embodiments, the SOT material portions 312 each individually comprises BiSb. The BiSb may have a (001) or a (012) orientation.
In other embodiments, the SOT material portions 312 each individually comprises a topological insulator, a topological half-Heusler alloy, or a weakly oxidized heavy metal. The topological insulator may be BiSb, Bi2Se3, Bi2T3, (BiSb)2Te3, or SnTe. The topological half-Heusler alloy may be YPtBi, LuPtBi, LuPdBi, ScPtBi, YAuPb, LaPtBi, or CePtBi. The weakly oxidized heavy metal may be WOx, TaOx, or PtOx, wherein x is a number greater than zero.
The SOT material portion 312 may comprise a single SOT material. In other embodiments, the SOT material portion 312 may comprise a stacked layer as shown in
The SOT material portion 312 of
The SOT material portion 312 of
The SOT material portion 312 of
The SOT material sub-layer 410 may have a thickness in the z-direction of about 60 Å to about 200 Å. The SOT material sub-layer 410 may be referred to herein as a spin Hall effect (SHE) layer, a spin orbit torque (SOT) layer. The SOT material sub-layer 410 may comprise a topological insulator, a topological half-Heusler alloy, or a weakly oxidized heavy metal. The topological insulator may be BiSb, Bi2Se3, Bi2T3, (BiSb)2Te3, or SnTe. The topological half-Heusler alloy may be YPtBi, LuPtBi, LuPdBi, ScPtBi, YAuPb, LaPtBi, or CePtBi. The weakly oxidized heavy metal may be WOx, TaOx, or PtOx, wherein x is a number greater than zero.
In embodiments where the SOT material portion 312 comprise one or more electrodes 402, the one or more electrodes 402 may each individually comprise a nonmagnetic, low resistivity metal. For example, the one or more electrodes 402 may each comprise Ru, CuAg, Ta(alpha), W(alpha), Mo, Cu, Ag, Rh, Pt, among others. Low to moderate resistivity magnetic materials can be used if the one or more electrodes 402 are far enough away not to interfere with FM/SOT interactions. The thickness of each of the one or more electrodes 402 in the z-direction is greater than or equal to about 100 Å.
The cap layer 418 may comprise nonmagnetic, 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, beta-Ta, and beta-W; or nitrides, oxides, or borides of above-mentioned 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 numeral. The cap layer 418 can comprise multilayer combinations of the above-mentioned materials, and the overall thickness of the cap layer 418 in the y-direction is less than or equal to about 100 Å (nominally about 15 Å to about 50 Å). Furthermore, lower resistivity metals may be used in the cap layer 418 if the barrier layer 416 or the bottom portion of the cap layer 418 has a high resistivity and is thick enough to reduce FM shunting.
The seed layer 404 may comprise the same material(s) as the cap layer 418, and the seed layer 404 may be multilayered. For example, the seed layer 404 may comprise: nonmagnetic, 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, beta-Ta, and beta-W; or nitrides, oxides, or borides of above-mentioned 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 numeral. The thickness of the seed layer 404 in the z-direction is less than or equal to about 100 Å (nominally about 15 Å to about 50 Å). The seed layer 404 and the cap layer 418 can each individually be thicker if magnetic electrodes are used in the device stack.
The texture layer 452 may comprise RuAl, where Ru is between about 45% to about 55%, CrMo, where Mo is between about 25% to about 50%, or multilayers of CrMoX with CrX, where X=Ti, Ru, Mo, or W. The texture layer 452 has a (001) texture. The texture layer 452 may have a B2 or BCC crystalline structure where the a-axis lattice parameter is about 2.95 Å to about 3.05 Å. The texture layer 452 has a thickness in the y-direction of about 30 Å to about 50 Å.
Each of the buffer layer 406, the interlayer 412, the barrier layer 416, and the nucleation layer 408 comprises magnetic or nonmagnetic Heusler alloys, where the Heusler alloys may be full Heusler alloys (i.e., X2YZ) or half Heusler alloys (i.e., XYZ). Full X2YZ type Heusler alloys generally have L21, cF16, or C1b type structures with an a-axis between about 5.70 Å and about 6.20 Å, which perfectly matches to RuAl or CrMo texturing layer 452. Half XYZ type Heusler alloys generally have a B2 type or Pm-3m type structure with a-axis between about 2.85 Å to about 3.10 Å. However, the type or structure may vary with respect to both half and full Heusler alloys. For instance, RuMnAl, RhMnAl, and Al2CuRh, have a Pm-3m structure, and Ni2MnAl and Mn2NiAl have cF16 structures while Al2NiMn has a B2 structure.
With both full and half Heusler alloys, X may be one of Li, Mg, Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Cd, Ir, Pt, or Au; Y may be one of Li, Be, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, or W; and Z may be one of B, Mg, Al, Si, Zn, Ga, Ge, As, In, Sn, Sb, Pb, or Bi. Some nonmagnetic Heusler alloy examples include Ti2MnAl, Fe2VAl (a-axis=5.78 Å), Cr2CoAl (a-axis-5.88 Å), CoTiSb (a-axis=5.88 Å), Mn2VSi, V2VAl (a-axis=6.14 Å), [Mn1-xCox]2VAl (x=0.5) (a-axis=6.05 Å), [Mn1-xCox]2VSi (x=0.25) (a-axis=6.18 Å), and CoMnNbAl, CoZrFeAl. Magnetic Heusler alloy examples having large spin polarizations include Co2MnSb (a-axis-5.94 Å), Co2MnGe (a-axis-5.75 Å), CoMnSb (a-axis-5.90 Å) NiMnSb, Co2FeGe, Co2MnSn, and Co2MnFeGe, each of which does not readily mix with the SOT material sub-layer 410.
Moreover, each of the buffer layer 406, the interlayer 412, the barrier layer 416, and the nucleation layer 408 comprises: (1) amorphous/nanocrystalline layers formed from Heusler alloys in combination with elements, or alloy layers that don't readily mix with the SOT or FM layers, or uniform alloys formed by co-sputtering Heusler alloys with other elements, or alloys which don't readily intermix with SOT or FM layer, or (2) polycrystalline Heusler alloys, which are epitaxial layers in the SOT material portion 312. With respect to amorphous/nanocrystalline buffer layers 406, nucleation layers 408, interlayers 412, and barrier layers 416, thin polycrystalline Heusler alloys (both magnetic and nonmagnetic, and full or half Heusler alloys) can be used when alloyed with other elements that don't readily mix with the SOT material sub-layer 410, such as Cu, Ag, Ge, Mn, Ni, Co Mo, W, Sn, B, and In, or in alloy combinations with one or more of aforementioned elements, such as CuAg, CuNi, CoCu, AgSn. The nucleation layer 408 can also be just very thin (e.g., dusting) layers of these aforementioned elements, or in very thin alloy combination of these elements like CuAg, CuNi, CoCu, and AgSn.
Utilizing amorphous or nanocrystalline layers formed from Heusler alloys alloyed with other elements that don't readily mix with the SOT material sub-layer 410 forms effectively nonmagnetic amorphous/nanocrystalline buffer and nucleation layers 406, 408 in several situations: (1) after deposition and room temperature (RT) intermixing; (2) post annealing prior to the SOT material sub-layer 410 deposition; (3) in single uniform composition layer nonmagnetic amorphous/nanocrystalline alloy depositions with single alloy targets; or (4) co-sputtered with targets which contain the elements of the Heusler alloy and the non-readily mixed multi-elemental combination of elements mentioned above.
The interlayer 412 and the barrier layer 416 are formed in a similar fashion as the buffer and nucleation layers 406, 408 (although the nucleation layer 408 can also be just these aforementioned elements or any nonmagnetic alloy combination of these elements); however, it is not necessary that after deposition and RT intermixing that the resulting graded interlayer 412 or barrier layer 416 be amorphous as long as the resulting layer has a high resistance and reduces interlayer 412/barrier layer 416 intermixing with the SOT material sub-layer 410.
With respect to polycrystalline Heusler alloys, thin layers of Heusler alloys, both magnetic and nonmagnetic, full or half Heusler alloys, can be used as the buffer layer 406, the interlayer 412, the barrier layer 416, and/or the nucleation layer 408 in (100) textured layer SOT devices (SOT orientation in this scenario is (012)). Heusler alloys generally have higher resistivities then the FM layer(s) 303, and transport spin currents or yield high spin polarization, while providing and maintaining (100) growth. Heusler alloys further have excellent lattice matching capabilities to MgO tunnel barrier layers and to bcc FM alloys. (100) texturing layers, such as the texture layer 452, can be used to establish the (100) texture, and non-magnetic Heusler X2YZ or XYZ having cF16 (C1b, L21) or B2 structures can be used to transmit the texture to the SOT material sub-layer 410, which in turn grows a strong (012) texture for the SOT material sub-layer 410.
Other non-Heusler, nonmagnetic materials that could be used for one or more of the epitaxial buffer layer 406, interlayer 412, and/or barrier layer 416 for epitaxial growth 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% to about 50%, CrMoTi, Cr, MoV, CrMoW; or CrXY, where X and Y are each individually selected from the group consisting of: Al, Ti, Mn, Co, Ni, Ru, Mo, Rh, W, and V.
In some embodiments, the barrier layer 416 can be formed from thin ceramic oxide or nitride layers like TiN, WN, SiN, and Al2O3, and MgO can be used as the barrier layer 416 or in combination with other high resistive nonmagnetic material layers. The top portion of a multilayer barrier layer 416 may also be comprise of high resistivity heavier metal amorphous or amorphous/nanocrystalline metals like NiFeTa, NiTa, NiHf, NiFeHf, CoHf, CoFeHf, NiWTa, NiFeW, NiW, and WRe; nanocrystalline metals like beta-Ta and beta-W; or nitrides, oxides, or borides of the aforementioned elements or alloys like NiTaN, NiFeTaN, NiWTaN, NiWN, WReN, TaN, WN, TaOx, WOx, TaBx, WBx, HfBx, NiHB, NiFeHfB, and CoHfB, where x is a numeral. The bottom portion of the barrier layer 416 can be an amorphous/nanocrystalline material formed from Heusler alloys or other magnetic alloy materials when combined with aforementioned non-interacting elements or alloy combinations of those elements. Higher resistivity nonmagnetic alloys, such as CuAg, CuNi, NiAg, CoCu, NiAl, RuAl, RhAl, and AgSn, can also be used as the barrier layer 416. The barrier layer 416 can also be a polycrystalline nonmagnetic Heusler alloy or half 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% to about 50%, CrMoTi, Cr, MoV, CrMoW; or CrXY, where X and Y are each individually selected from the group consisting of: Al, Ti, Mn, Co, Ni, Ru, Mo, Rh, W, and V; or in any combination of these material layers which has a higher resistive non-interacting layer next to the FM layer, among others.
When alloyed with nonmagnetic materials, examples of high resistive amorphous barrier layer 416 materials include Ge/CoFe/CuAg (as used here “/” denotes separate sub-layers in a stack or layer) (where Ge/CoFe may form a single layer at room temperature or may be deposited as an alloy layer, and where Ge has a thickness of about 6 Å, CoFe has a thickness of about 4 Å, and CuAg has a thickness of about 3 Å), CuAg/Ge/CoFe/CuAg (where CuAg/Ge/CoFe may form a single layer at room temperature or may be deposited as an alloy layer, and where CuGe has a thickness of about 3 Å, Ge has a thickness of about 5 Å, CoFe has a thickness of about 4 Å, and CuAg has a thickness of about 2 Å), or thin nonmagnetic alloy layers like CoFeGe, NiFeGe, CoFeGeAg, etc. (alloy composition for alloys with Ge should be greater than about 44 at. % Ge to render the alloy nonmagnetic). When alloyed with nonmagnetic materials, additional examples of elements, compounds, or crystalline/amorphous/nanocrystalline materials that may be utilized as the barrier layer include: Ge/CoFe/NiFeTaN (where Ge/CoFe may form a single layer at room temperature or may be deposited as an alloy layer, and where Ge has a thickness of about 6 Å, CoFe has a thickness of about 4 Å, and NiFeTaN has a thickness of about 3 Å); Ge/CoFe/MgO (where Ge/CoFe may form a single layer at room temperature or may be deposited as an alloy layer, and where Ge has a thickness of about 6 Å, CoFe has a thickness of about 4 Å, and MgO has a thickness of about 3 Å); and MgO/Ge/CoFe (where Ge/CoFe may form a single layer at room temperature or may be deposited as an alloy layer, and where MgO has a thickness of about 3 Å, Ge has a thickness of about 6 Å, and CoFe has a thickness of about 4 Å). Examples of a barrier layer 416 or an interlayer 412 using alloys with X2YZ Heusler alloys would be Ge/Co2FeGe (which may form a single layer at room temperature or may be deposited as an alloy layer, and where Ge is about 4 Å thick and Co2FeGe is about 5 Å thick); or using alloys with XYZ half Heusler alloys like Ge/CoFeGe (which may form a single layer at room temperature or may be deposited as an alloy layer, where Ge is about 3 Å thick and CoFeGe is about 6 A Å thick); and Ge/CoA (which may form a single layer at room temperature or may be deposited as an alloy layer), Ge/FeA (which may form a single layer at room temperature or may be deposited as an alloy layer), or Ge/NiA (which may form a single layer at room temperature or may be deposited as an alloy layer), where A can be one or more elements belonging to full Heusler alloys X2YZ or half Heusler alloys XYZ; or used in combination with very thin (i.e., dusting layers about 1 Å to about 5 Å thick) of nonmagnetic seed or capping layers of alloys of CuAg, NiCr, CoCu, AgSn, etc., such as Ge/X2YZ/CuAg, Ge/X2YZ/CuNi, CuNi/Ge/X2YZ, or CuAg/Ge/X2YZ/CuNi. The alloy composition should be nonmagnetic as in the case of alloys with one of the aforementioned non-interacting elements or alloys of these elements like Ge where Ge exceeds about 44 at. % to render the alloy nonmagnetic.
The barrier layer 416 may comprise multilayer stacks comprising one or more of the aforementioned elements, compounds, or crystalline/amorphous/nanocrystalline metals. The thickness in the z-direction of the barrier layer 416 may be about 3 Å to about 100 Å, depending on resistivity of the barrier layer 416, and how effective the barrier layer 416 is at reducing FM intermixing and FM shunting in the SOT material portion 312.
The interlayer 412 may comprise any of the aforementioned elements, compounds, or crystalline/amorphous/nanocrystalline metals that the barrier layer 416 may comprise. Additionally, the interlayer 412 may comprise nonmagnetic 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 in conjunction with magnetic alloys such as CoA, FeA, and NiA, where A can be one or more elements belonging to full Heusler alloys X2YZ or half Heusler alloys 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; and where Z is selected from the group consisting of: B, Al, Si, Ga, Ge, As, In, Sn, Sb, and Bi. The magnetic alloys or Heusler alloys should combine with other layers, combinations of elements, or other alloys to form a nonmagnetic layer or multilayer stack after room temperature deposition and intermixing, or deposited as a nonmagnetic single layer alloy, or in combinations thereof. The overall total thickness of the interlayer 412 is less than about 20 Å, such as about 3 Å to about 15 Å. Nonmagnetic polycrystalline Heusler alloys may also be used for the interlayer 412, such as V2VAl or [Mn0.5Co0.5]2VAl, etc.
The interlayer 412 should have higher resistivity and be nonmagnetic. Thin, high resistivity, low Z ceramic oxide and nitride layers of TiN, SiN, Al2O3, MgO, thin layers can be used in the interlayer 412. Furthermore, other materials that may be used as the interlayer 412 if not disposed in direct contact with the SOT material sub-layer 410 include: high resistivity, heavier metal amorphous/nanocrystalline metals such as NiFeTa, NiTa, NiWTa, NiFeW, NiW, and WRe; nanocrystalline metals like beta-Ta or beta-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, nonmagnetic alloys which don't readily interact with the SOT material sub-layer 410, such as Cu, Ag, Ge, Mn, Ni, Co Mo, W, Sn, B, In, and multi-element alloys combinations thereof, like CuAg, CuNi, NiAg, CoCu, NiAl, RuAl, RhAl, CuCo, and AgSn.
Examples of high resistive, amorphous materials for the interlayer 412 include Ge (6 Å)/CoFe (4 Å)/CuAg (3 Å) (which may form a single layer at room temperature or may be deposited as an alloy layer), CuAg (3 Å)/Ge (5 Å)/CoFe (3 Å)/CuAg (2 Å) (which may form a single layer at room temperature or may be deposited as an alloy layer), or single alloy nonmagnetic layers of CoFeGe, NiFeGe, CoFeGeAg, among others. The interlayer 412 may comprise thin multilayer stacks consisting of the aforementioned elements, compounds, or crystalline/amorphous/nanocrystalline layers as long as the overall multilayer stack is nonmagnetic and has a high resistivity.
Magnetic alloys and magnetic Heusler alloys can be used if used in combinations with other elements or alloys above such that when deposited, the materials intermix at room temperature, or after post annealing, to form a nonmagnetic stack. Examples include layers of NiFeX, CoFex, NiX, FeX, CoX, where X is an element that does not readily interact with BiSb, such as Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In, or magnetic Heusler alloys deposited on non-interacting element or alloy layers like Ge layers and in single alloy deposition layers where the resulting Ge content in the intermixed alloy renders it nonmagnetic (e.g., in the case of alloying with Ge the Ge content should be greater than or equal to about 44 at. %); or in combination with sufficiently thick layers of elements which do not readily interact with BiSb, such as Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In, to form multi-element, nonmagnetic, high resistivity combinations thereof; or single polycrystalline nonmagnetic Heusler layers.
Another example of materials that may be used for the interlayer 412 include: Ge/CoFe/NiFeTaN (where Ge/CoFe may form a single layer at room temperature or may be deposited as an alloy layer, and where Ge has a thickness of about 6 Å, CoFe has a thickness of about 4 Å, and NiFeTaN has a thickness of about 3 Å).
Moreover, materials similar to the interlayer 412 can be used in the barrier layer 416, such as Cu, Ag, Ge, Mn, Ni, Co Mo, W, Sn, B, In, and alloy combinations thereof, 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, where the Ge content is about greater than or equal to about 44 atomic percent (at. %). The Ge content being about greater than or equal to about 44 at. % ensures 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) such that the final thin multilayer interlayer 412 and/or barrier layer 416 after deposition mixing or post annealing is nonmagnetic.
In the SOT material portion 312 of
The nucleation layer 408 may comprise any of the same materials as the barrier layer 416 and/or interlayer 412; or a nanocrystalline to polycrystalline epitaxial layer like a nonmagnetic Heusler alloy; or bcc or B2 non-interacting material with the SOT. Additionally, the nucleation layer 408 may comprise elements which do not readily interact with the SOT material sub-layer 410, such as Cu, Ag, Ge, Mn, Co, Ni, Mo, Sn, In, B, and W; or in multiple element alloy combinations thereof, such as CuAg, CuNi, CuCo, and AgSn; or low Fe alloys thereof, or one or more of these elements or combination of elements. Further examples of materials that may be used as dusting layers of the nucleation layer 408 include Ge having a thickness between about 2 Å to about 6 Å, CuAg having a thickness between about 2 Å to about 5 Å, and CuNi having a thickness between about 2 Å to about 5 Å. The nucleation layer 408 may have a thickness in the y-direction of about 1 Å to about 10 Å.
The buffer layer 406 may comprise any of the same materials as the barrier layer 416 and/or interlayer 412. The buffer layer 406 may further comprise any of the above-listed materials used in the interlayer 412, such as a single alloy layer or layer combinations; nonmagnetic alloys or multilayer stacks comprising one or more of the following elements Cu, Ag, Ge, Mn, Ni, Mo, and W; or multi-element alloy combinations thereof; or in conjunction with magnetic and or nonmagnetic alloys such as CoA, FeA, NiA, where A is one or more elements belonging to full Heusler alloys X2YZ or half Heusler alloys XYZ, where 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 magnetic alloy or Heusler alloys should combine with other elements such as Cu, Ag, Ge, Mn, Co, Ni, Mo, Sn, In, B, and W, or combine in multi-elemental alloy layers thereof, to form a nonmagnetic total stack buffer layer 406. The buffer layer 406 may be thin or relatively thick, such as having a thickness in the z-direction of about 5 Å to about 100 Å. A thicker buffer layer 406 can provide better migration resistance against elements from neighboring stacks getting into the SOT material sub-layer 410, or provide better migration resistance of the individual elements within the SOT material sub-layer 410 out of the SOT material sub-layer 410. The buffer layer 406 can be made thicker by lamination of layers to better control SOT nucleation/growth and texture.
Additional examples of materials that can be used for the buffer layer 406 include: [Ge/X2YZ]*n laminations, [Ge/XYZ]*n laminations, and [Ge/XYZ]*n laminations, where n is a whole numeral; Ge-enriched X2YZ and Ge-enriched XYZ single layer alloys such that the buffer layer 406 is nonmagnetic (i.e., Ge>44%); [Ge (6 Å)/Co2(MnFe)Ge (4 Å)]*4, [Ge (3 Å)/CoFeGe (6 Å)]*3, and [Ge (6 Å)/NiFe (4 Å)]+n; and with Ge alloyed or layered with NiA, FeA, CoA in lamination, where A is one or more elements belonging to full Heusler alloys X2YZ or half Heusler alloys XYZ, for example, [Ge (6 Å)/NiA (4 Å)]+n] where 1<n<4. The overall buffer layer 406 has a thickness between about 10 Å to about 50 Å.
In the SOT material portion 312, the SOT material sub-layer 410 is deposited on the buffer layer 406 or the nucleation layer 408. As the SOT material sub-layer 410 is deposited, the SOT material sub-layer 410 may be doped or remain undoped. When the SOT material sub-layer 410 is undoped, the buffer layer 406 (or the nucleation layer 408) promotes the SOT material sub-layer 410 to grow a (001) crystal orientation. When the SOT material sub-layer 410 is doped, the buffer layer 406 (or the nucleation layer 408) promotes the SOT material sub-layer 410 to grow a (012) crystal orientation. The relatively non-interacting dopant used to promote the (012) orientation of the SOT material may be, a gas, a metal, a non-metal, or a ceramic material. To create a strong (012) texture, the entire SOT material sub-layer 410 need not be doped, only about the first 10 Å to about 50 Å of the SOT material sub-layer 410 immediately adjacent to the buffer layer 406 (or the nucleation layer 408) needs to be doped. The remaining SOT material sub-layer 410 may then be deposited as undoped SOT material on top of the initially doped portion of SOT material already deposited. Doping only a portion of the SOT material sub-layer 410 is sufficient to promote and grow a (012) orientation of the entire SOT material sub-layer 410. The SOT material portion 312 can achieve a spin Hall angle (SHA) of about 2 or larger when the SOT material sub-layer 410 has a (012) orientation or a (001) orientation.
In some embodiments, the SOT material sub-layer 410 may be BiSb. Examples of the process of doping BiSb is described in co-pending patent application titled “Novel Doping Process To Refine Grain Size For Smoother BiSb Film Surface,” U.S. application Ser. No. 17/854,568, filed Jun. 30, 2022, assigned to the same assignee of this application, which is herein incorporated by reference.
With respect to each of the SOT material portions 312 of
The buffer layer 406 and the nucleation layer 408 not only provide a strong (001) or (012) texture, the buffer layer 406 and the nucleation layer 408 also prohibit or minimize the migration of the individual elements of the SOT material sub-layer 410 from diffusing into or through the buffer layer 406 and the nucleation layer 408. Because the buffer layer 406, the nucleation layer 408, and/or the interlayer 412 has high resistivity (e.g., about 300 pohm-cm), shunting of the SOT material sub-layer 410 is minimized, which improves thermal stability.
Thus, by having a layered stack of an FM layer and a SOT material portion, the spin Seebeck effect and the inverse spin Hall effect can be combined to measure a temperature gradient. Increasing the number of SOT material portions and the FM layers increases the output voltage, making the temperature gradient easier to detect. Providing a heat sink increases the thermal gradient, which also increases the output voltage, making it easier to detect the temperature gradient.
In one embodiment, a temperature detection device, comprising a temperature detection stack, comprising a first antiferromagnetic (AFM) layer, a first ferromagnetic (FM) layer disposed on the first AFM layer, a spin-orbit torque (SOT) material layer disposed on the first FM layer, wherein the SOT material layer further comprises one or more SOT material layer portions, a second FM layer disposed on the SOT material layer, and a second AFM layer disposed on the second FM layer.
In another embodiment the temperature detection device, further comprising a heat sink, wherein the heat sink is adjacent to the temperature detection stack.
In yet another embodiment, the temperature detection device, wherein the temperature detection device includes a media facing surface (MFS) and wherein a first SOT material layer portion of the one or more SOT material layer portions is recessed from the MFS.
In another embodiment, the temperature detection device, wherein the first AFM layer has a surface at the MFS.
In another embodiment, the temperature detection device, wherein the SOT material layer further comprises an insulating material layer portion disposed between the first SOT material layer portion and the MFS.
In yet another embodiment, the temperature detection device, wherein the SOT material layer further comprises one or more insulating material layer portions, wherein a first insulating material layer portion of the one or more insulating material layer portions is disposed between the one or more SOT material layer portions and the heat sink.
In another embodiment, the temperature detection device, wherein the one or more SOT material layer portions is a first SOT material layer portion and a second SOT material layer portion.
In yet another embodiment, the temperature detection device, wherein the one or more insulating material layer portions further comprises a second insulating material layer portion, wherein the second insulating material layer portion is disposed between the one or more SOT material layer portions and a MFS.
In yet another embodiment, the temperature detection device, wherein the temperature detection stack has a first thickness and the heat sink has a second thickness, wherein the first thickness is greater than the second thickness.
In another embodiment, the temperature detection device, wherein the SOT material layer further comprises: a first insulating material layer portion and a second insulating material layer portion, wherein the one or more SOT material layer portions comprises a first SOT material layer portion, a second SOT material layer portion, and a third SOT material layer portion, and wherein the first SOT material layer portion, the second material layer portion, and the third SOT material layer portion are alternating with the first insulating material layer portion and the second insulating material layer portion.
In another embodiment, the temperature detection device, wherein the SOT material layer has a first length, and the first FM layer has a second length, wherein the first length is less than the second length.
In another embodiment, the temperature detection device, wherein the one or more SOT material layer portions comprises BiSb.
In yet another embodiment, the temperature detection device, wherein the one or more SOT material layer portions comprises a topological insulator, a topological half-Heusler alloy, or a weakly oxidized heavy metal.
In yet another embodiment, the temperature detection device, wherein the topological insulator is BiSb, Bi2Se3, Bi2T3, (BiSb)2Te3, or SnTe, the topological half-Heusler alloy is YPtBi, LuPtBi, LuPdBi, ScPtBi, YAuPb, LaPtBi, or CePtBi, and the weakly oxidized heavy metal is WOx, TaOx, or PtOx, wherein x is a number greater than zero.
In another embodiment, the temperature detection device of claim 1, wherein the one or more SOT material layer portions comprises a seed layer.
In another embodiment, a magnetic recording head comprising the temperature detection device.
In one embodiment, a temperature detection device, comprising a spin-orbit torque (SOT) portion having a first surface at a MFS, a heat sink portion disposed adjacent the SOT portion which is recessed from the MFS, a first ferromagnetic (FM) portion disposed adjacent to a second surface of the SOT portion and the heat sink portion, wherein the first FM portion has a surface at the MFS, a second FM portion disposed adjacent to a third surface of the SOT portion and opposite the second surface, wherein the second FM portion has a surface at the MFS, an first antiferromagnetic (AFM) portion spaced from the SOT portion and disposed adjacent to the first FM portion and the heat sink portion, wherein the first AFM portion has a surface disposed at the MFS, and a second AFM portion spaced from the SOT portion and disposed adjacent the second FM portion and the heat sink portion, wherein the second AFM portion has a surface disposed at the MFS.
In another embodiment, the temperature detection device, wherein the SOT portion comprises a seed layer, a buffer layer, a nucleation layer, a SOT material sub-layer, an interlayer, a barrier layer, a cap layer, and an electrode.
In another embodiment, the temperature detection device, wherein the SOT portion comprises a seed layer, a texture layer, a buffer layer, a nucleation layer, a SOT material sub-layer, a first interlayer, a second interlayer, a barrier layer, and a cap layer.
In yet another embodiment, the temperature detection device, wherein the SOT portion comprises a seed layer, a texture layer, a buffer layer, a SOT material sub-layer, an interlayer, and a cap layer.
In another embodiment, a magnetic recording head comprising the temperature detection device.
In another embodiment, the magnetic recording head, further comprising a read head and a write head, wherein the temperature detection device is disposed adjacent to the write head.
In one embodiment, a temperature detection device, comprising a spin-orbit torque (SOT) portion having a first surface at a media facing surface (MFS), a second surface opposite the first surface, a third surface connecting the first and second surfaces, and a fourth surface opposite the third surface, wherein the first surface has a first length and the third surface has a second length, and wherein the first length is greater than the second length, a heat sink portion disposed adjacent the SOT portion, a ferromagnetic (FM) portion disposed adjacent to the SOT portion, and an antiferromagnetic (AFM) portion spaced from the SOT portion and disposed adjacent the FM portion and the heat sink portion.
In another embodiment, the temperature detection device, wherein the FM portion has a fifth surface disposed at the MFS, a sixth surface opposite the fifth surface, a seventh surface connecting the fifth surface to the sixth surface, and an eighth surface opposite the seventh surface, wherein the fifth surface has a third length, wherein the seventh surface has a fourth length, and wherein the third length is greater than the first length.
In another embodiment, the temperature detection device, wherein the fourth length is greater than the third length.
In yet another embodiment, a magnetic recording head comprising the temperature detection device.
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.
This application claims benefit of U.S. Provisional Patent Application Ser. No. 63/439,507, filed Jan. 17, 2023, which is herein incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63439507 | Jan 2023 | US |
