[9a-E207-1~9] 10.4 Spintronics in semiconductor, topological material, superconductor, and multiferroics

9:30 AM - 9:45 AM JST(12:30 AM - 12:45 AM UTC)Presentation by Applicant for JSAP Young Scientists Presentation AwardEnglish Presentation

[9a-E207-3] Thermally Robust Bisb(Ge) Topological Heterostructures Engineered for Advanced Spin-Orbit Torque Technologies

〇(P)Manoj Talluri¹, Zhenchao Wen¹, Seiji Mitani¹, Hiroaki Sukegawa¹, Tuo Fan², Brian York³, Xiaoyong Liu³, Maki Maeda², Quang Le³ (1.NIMS, 2.Western Digital (JP), 3.Western Digital (US))

Keywords:

Topological Insulator BiSb,Ge alloying,Buffer and interlayer engineering

Topological insulators like BiSb offer strong spin-orbit coupling for spin-orbit torque(SOT) devices, but practical integration is hindered by poor film quality on SiO₂ substrate and limited thermal stability. I introduced a NiFeGe buffer to promote homogeneous BiSb growth and alloyed Ge into BiSb via lamination, keeping Ge<10% to preserve topological character. The optimized BiSb(Ge) films exhibit a dominant (012) texture with low surface roughness and stable orientation after annealing to 250^oC. X-ray reflectivity indicates oxidation at the SiO₂/NiFeGe interface; inserting a thin TiN_x underlayer suppressed oxidation and improved thermal robustness. We estimated SOT efficiency through spin-torque ferromagnetic resonance (ST-FMR) on microfabricated devices. TiN_x-engineered stacks retain high SOT efficiency of 0.39 after 250^oC annealing vs 0.20 in stacks without TiN_x. These results demonstrate careful alloying with interfacial engineering enables thermally stable BiSb-based SOT devices.