Presentation Information
[8p-E207-16]BEOL-Compatible Topological Semimetal YPtBi with High Spin-Orbit Torque Efficiency Enabled by Berry-Phase Monopole Engineering
〇(D)Sho Kagami1, Ohiro Fujie1, Quang Le2, Brian York2, Cherngye Hwang2, Xiaoyong Liu2, Son Le2, Maki Maeda3, Tuo Fan3, Yu Tao3, Hisashi Takano3, Pham Nam Hai1 (1.Science Tokyo, 2.W.D. Inc., Great Oaks, 3.W.D. Inc., Fujisawa)
Keywords:
Topological Semimetal,Spin-Orbit Torque,SOT-MRAM
SOT-MRAM is a promising next-generation nonvolatile memory owing to its high speed, endurance, and low power consumption. However, SOT materials that retain high spin-current-generation efficiency after annealing at 400 deg C have not been established. We investigated YPtBi/Mo/CoFeB/MgAl2O4/Ta multilayers with different YPtBi compositions and annealing conditions. Stoichiometric samples were annealed at 300 or 400 deg C, while a Y-poor sample was annealed at 400 deg C. The Y-poor composition is expected to enhance interfacial spin transparency, while Mo substitution at Y vacancies may increase spin Hall conductivity through Berry-phase engineering. After annealing at 400 deg C, the stoichiometric and Y-poor samples retained high effective perpendicular anisotropy fields of 6.9 and 6.6 kOe, respectively. The Y-poor sample achieved an effective spin Hall angle of 2.1 and a spin Hall conductivity of (4.1 × 10^{5},(/2e),^{-1},m^{-1}), demonstrating the potential of YPtBi as a BEOL-compatible SOT source.