Title: Conductive topological antiferromagnet for PMA SOT-MRAM
Presenters: MahendraDC and Shan X. Wang
Abstract: High spin-orbit torque (SOT) generated from quantum materials show promise for next generation magnetic memory and logic devices. We studied the SOT on magnetron-sputtered thin film MnPd (x nm)/Co20Fe60B20 (5 nm) heterostructures by using second harmonic Hall (SHH) and spin-torque ferromagnetic resonance (ST-FMR) techniques. The spin torque efficiency (θ_(s,y)) corresponding to in-plane anti-damping like torque from 400 ℃ post annealed MnPd thin films grown on thermally oxidized silicon substrate was determined to be 0.38-0.48 with the spin conductivity (σ_(s,y)) ~ 5.00-6.32 × 105 ℏ⁄2e Ω-1m-1. The drift-diffusion model estimated vertical spin diffusion length is 6.32-6.56 nm. In addition to the in-plane anti-damping and field like torques sizeable out of plane anti-damping like torque has been observed. The out of plane anti-damping like torque can switch perpendicular magnetization without the need of external magnetic field in addition to the reduction of critical switching current density. We also observed room temperature switching of in-plane CoFeB via the SOT from MnPd detected by unidirectional spin Hall magnetoresistance. The planar Hall effect and anisotropic magnetoresistance observed at room temperature in the MnPd thin films imply to the topological properties present in these films. High σ_(s,y) and robust against the 400 ℃ 30 min post annealing, long spin diffusion length, observation of out of plane anti-damping like torque, low damping constant of CoFeB grown on MnPd, and SOT switching of CoFeB provide a path for the use of Dirac topological antiferromagnetic MnPd as a spin channel in ultrafast magnetic memory and logic devices.
ASCENT Task: 2776.056
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