Giant interface spin-orbit torque in NiFe/Pt bilayers*

Abstract

The current-induced spin-orbit torque (SOT) plays a dominant role to manipulate the magnetization in a heavy metal/ferromagnetic metal bilayer. We separate the contributions of interfacial and bulk spin-orbit coupling (SOC) to the effective field of field-like SOT in a typical NiFe/Pt bilayer by planar Hall effect (PHE). The effective field from interfacial SOC is directly measured at the transverse PHE configuration. Then, at the longitudinal configuration, the effective field from bulk SOC is determined, which is much smaller than that from interfacial SOC. The giant interface SOT in NiFe/Pt bilayers suggests that further analysis of interfacial effects on the current-induced manipulation of magnetization is necessary.