High-efficient spin orbit torque generated by topological semimetal YPtBi deposited on oxidized Si substrates

Abstract

Half-Heusler alloy topological semimetal YPtBi is a promising candidate for an efficient spin current source in spin–orbit torque (SOT) devices thanks to its large spin Hall angle θSH (>1) and high thermal stability (600 °C). However, the spin Hall effect has been studied so far in high quality YPtBi(111) thin films deposited on c-Sapphire substrates. In this work, we study the SOT performance of sputtered YPtBi films deposited on SiO2/Si substrates. We realized YPtBi(110) thin films with large θSH of 1.3 at a relatively high conductivity of 1.4 × 105 Ω−1 m−1. The spin Hall conductivity of YPtBi(110) is even better than those of YPtBi(111) thin films deposited on c-Sapphire substrates, despite the lower crystal quality. Our results pave the way for using YPtBi in integrated SOT devices on Si substrates.