High Spin Hall Conductivity Induced by Ferromagnet and Interface

Spin-orbit-torque (SOT) offers a highly attractive perspective for manipulating magnetization dynamics in magnetic nanostructures. SOT is been observed and studied in various systems. However, limited by the efficiency, SOT-induced switching of the ultrahard ferromagnet is still extremely difficult and a further improvement in efficiency is requested. Here, the SOT is reported in chemically disordered soft Fe0.5Pt0.5 and Pt/Fe0.5Pt0.5 bilayers. Due to the magnetization-strengthened spin Hall effect, the damping-like torque efficiency and spin Hall conductivity (SHC) in Fe0.5Pt0.5 reach 1.11 and 1.08 x 10(6) PLANCK CONSTANT OVER TWO PI/2e omega(-1) m(-1) respectively, much higher than those in conventional materials. Furthermore, the Pt/Fe0.5Pt0.5 interface enhances SHC to a total of 2.93 x 10(6) PLANCK CONSTANT OVER TWO PI/2e omega(-1) m(-1) due to the interfacial symmetry breaking. This system can be used to partially switch the magnetization of ultra-hard exchange-spring system with a switching field of 1T by applying a relatively low current. This finding will push forward the development of SOT devices with ultrahigh-density and low-power consumption.

Automated summary

Spin-orbit-torque (SOT) offers a highly attractive perspective for manipulating magnetization dynamics in magnetic nanostructures. The efficiency of SOT-induced switching of ultrahard ferromagnets is still a challenge. In this study, SOT is reported in chemically disordered Fe0.5Pt0.5 and Pt/Fe0.5Pt0.5 bilayer materials, with high efficiency and enhanced spin Hall conductivity (SHC). The Pt/Fe0.5Pt0.5 interface further enhances SHC due to interfacial symmetry breaking, enabling partial magnetization switching in an ultra-hard exchange-spring system with a low current.