Bismuth antimony alloys for use as topological insulators
A SOT device includes a bismuth antimony dopant element (BiSbE) alloy layer over a substrate. The BiSbE alloy layer is used as a topological insulator. The BiSbE alloy layer includes bismuth, antimony, AND a dopant element. The dopant element is a non-metallic dopant element, a metallic dopant element, and combinations thereof. Examples of metallic dopant elements include Ni, Co, Fe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, or combinations thereof. Examples of non-metallic dopant elements include Si, P, Ge, or combinations thereof. The BiSbE alloy layer can include a plurality of BiSb lamellae layers and one or more dopant element lamellae layers. The BiSbE alloy layer has a (012) orientation.
1. A spin-orbit torque (SOT) device, comprising:
a substrate; and
a bismuth antimony dopant element (BiSbE) alloy layer over the substrate, the BiSbE alloy layer having a (012) orientation, the BiSbE alloy layer comprising,
bismuth;
antimony; and
one or more dopant element lamellae layers at least at a top edge of the BiSbE alloy layer, each of the one or more dopant element lamellae layers comprising a dopant element comprising a material selected from a group consisting of a non-metallic dopant element, a metallic dopant element, and combinations thereof.
2. The SOT device of claim 1 , wherein the dopant element is the metallic dopant element selected from a group consisting Ni, Co, Fe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, and combinations thereof.
3. The SOT device of claim 1 , wherein the dopant element is the non-metallic dopant element is selected from a group consisting Si, P, Ge, and combinations thereof.
4. The SOT device of claim 1 , wherein the BiSbE alloy layer comprises the dopant element from 0.5 atomic % to 15 atomic %.
5. The SOT device of claim 1 , wherein the BiSbE alloy layer comprises Bi 1-x Sb x E wherein x is 0.05<x<0.22.
6. The SOT device of claim 1 , wherein the BiSbE alloy layer is formed to a thickness from 20 Å to 200 Å.
7. A SOT MRAM device, comprising the SOT device of claim 1 , wherein the BiSbE alloy layer is a spin orbit material electrode proximate to a free perpendicular magnetic anisotropy ferromagnetic layer.
8. A SOT-based energy-assisted magnetic recording (EAMR) write heads, comprising the SOT device of claim 1 , wherein the BiSbE alloy layer is proximate to a spin-torque layer.
9. The SOT device of claim 1 , wherein the BiSbE alloy layer further comprises the one or more dopant element lamellae layers throughout the BiSbE alloy layer.
10. A spin-orbit torque (SOT) device, comprising:
a substrate; and
a bismuth antimony dopant element (BiSbE) alloy layer over the substrate, the BiSbE alloy layer having a (012) orientation, the BiSbE alloy layer comprising,
a plurality of BiSb lamellae layers; and
one or more dopant element lamellae layers, each of the dopant element lamellae layers comprising a material selected from a group a non-metallic dopant element, a metallic dopant element, and combinations thereof, wherein the one or more dopant element lamellae layers are at a bottom edge of the BiSbE alloy layer and throughout the BiSbE alloy layer.
11. The SOT device of claim 10 , wherein each of the dopant element lamellae layers comprises the metallic dopant element selected from a group consisting Ni, Co, Fe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, and combinations thereof.
12. The SOT device of claim 10 , wherein each of the dopant element lamellae layers comprises the non-metallic dopant element selected from a group consisting Si, P, Ge, and combinations thereof.
13. The SOT device of claim 10 , wherein the BiSbE alloy layer further comprises the one or more dopant element lamellae layers at a top edge of the BiSbE alloy layer.
14. The SOT device of claim 10 , wherein the BiSbE alloy layer further comprises the one or more dopant element lamellae layers modulated in the BiSbE alloy layer.
15. A SOT MRAM device, comprising the SOT device of claim 10 , wherein the BiSbE alloy layer is a spin orbit material electrode proximate to a free perpendicular magnetic anisotropy ferromagnetic layer.
16. A SOT-based energy-assisted magnetic recording (EAMR) write heads, comprising the SOT device of claim 10 , wherein the BiSbE alloy layer is proximate to a spin-torque layer.
17. The SOT device of claim 10 , wherein the BiSbE alloy layer comprises Bi 1-x Sb x E wherein x is 0.05<x<0.22.
18. A magnetoresistive random access memory (MRAM) device, comprising:
a bismuth antimony dopant element (BiSbE) alloy layer, the BiSbE alloy layer having a (012) orientation, the BiSbE alloy layer comprising,
bismuth;
antimony; and
one or more metallic dopant element lamellae layers throughout the BiSbE alloy layer, each of the one or more metallic dopant element lamellae layers comprising a metallic dopant element selected from a group consisting of Ni, Co, Fe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, and combinations thereof; and
a perpendicular magnetic anisotropy (PMA) ferromagnetic layer.
19. The MRAM device of claim 18 , wherein the BiSbE alloy layer comprises:
a plurality of BiSb lamellae layers comprising the bismuth and the antimony.
20. The MRAM device of claim 19 , wherein the BiSbE alloy layer comprises the one or more metallic dopant element lamellae layers at least at a bottom edge of the BiSbE alloy layer.
21. The MRAM device of claim 18 , wherein the PMA ferromagnetic layer is an annealed PMA ferromagnetic layer.
22. The MRAM device of claim 18 , wherein the BiSbE alloy layer has a roughness (R a ) of 14 Å or less after the PMA ferromagnetic layer is annealed.
23. The MRAM device of claim 18 , wherein the BiSbE alloy layer has a rocking curve of 11 degrees or less.
24. The MRAM device of claim 18 , wherein the BiSbE alloy layer is a topological insulator after the PMA ferromagnetic layer is annealed.