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arXiv · 2108.06927

Highly fcc-textured Pt-Al alloy films grown on MgO(001) showing enhanced spin Hall efficiency

Yong-Chang Lau·Takeshi Seki·Koki Takanashi
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Abstract

We report on a systematic comparative study of the spin Hall efficiency between highly face-centered cubic (fcc)-textured Pt-Al alloy films grown on MgO(001) and poorly-crystallized Pt-Al alloy films grown on SiO$_2$. Using CoFeB as the detector, we show that for Al compositions centering around $x = 25$, mainly L1$_{2}$ ordered Pt$_{100-x}$Al$_x$ alloy films grown on MgO exhibit outstanding charge-spin conversion efficiency. For Pt$_{78}$Al$_{22}$/CoFeB bilayer on MgO, we obtain damping-like spin Hall efficiency as high as $ξ_\textrm{DL} \sim +0.20$ and expect up to seven-fold reduction of power consumption compared to the polycrystalline bilayer of the same Al composition on SiO$_2$. This work demonstrates that improving the crystallinity of fcc Pt-based alloys is a crucial step for achieving large spin Hall efficiency and low power consumption in this material class.

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Yong-Chang Lau, Takeshi Seki, Koki Takanashi. 2021-08-16. Highly fcc-textured Pt-Al alloy films grown on MgO(001) showing enhanced spin Hall efficiency. https://doi.org/10.1063/5.0052544

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