Spin transparency of Pt-based heavy metal/ferromagnet interface

Strong spin-orbit torques (SOTs) in heavy metal/ferromagnet (HM/FM) systems can efficiently manipulate magnetization at the nanoscale. When the spin Hall effect of the HMs is the dominant source of the SOTs as is the case for many HM/FM systems, achieving high spin transparency (T_int) of the interface is of the same importance as achieving a large spin Hall ratio in the HMs [1-3] for obtaining a large damping-like SOT. In Pt-based HM/FM system where electrons mediate the spin transport, spin backflow [4,5] inevitably reduces T_int by more than 50% [6] while the“spin memory loss”can further reduce T_int if the interfacial spin-orbit coupling is strong [7-10]. In this talk, we will discuss the strategies developed to effectively minimize or even eliminate spin backflow and spin memory loss.