Crystal orientation dependence of spin Hall angle in epitaxial Pt/FeNi systems

Abstract

The development of spintronics applications using the spin-orbit torque from the spin Hall effect is expected to advance the low-power consumption of various information devices. However, the dependence of the spin Hall effect on the crystal symmetry of the material has not been studied in detail. In this work, we investigate the dependence of the spin Hall angle on crystal orientation for epitaxial Pt in Pt/FeNi systems by using multiple ferromagnetic resonance techniques. Our estimation of the spin Hall angle indicates that the efficiency of spin current generation via the spin Hall effect can vary depending on the direction in which the spin current flows out, while the direction of the charge current has less impact on this efficiency.