Strong orbital torque in Ti/Co1−xPtx bilayer

Abstract

Conventionally, spin–orbit torque (SOT) in a nonmagnet/ferromagnet bilayer was attributed to spin current generation in a nonmagnet. Recent discovery of the orbital generation mechanism enables an orbital version of spin–orbit torque. However, orbital torque requires an efficient orbital-to-spin conversion process, which is often weak in a conventional 3d ferromagnet. In this study, we demonstrated strong orbital torque in the Ti/Co1−xPtx bilayer, where Ti generates orbital current and Co1−xPtx converts orbital current into spin current. SOT efficiency increases with Pt concentration and reaches +0.18 at Co0.5Pt0.5 composition.