High spin mixing conductance and spin interface transparency at $Co_2Fe_{0.4}Mn_{0.6}Si$ Heusler alloy and Pt interface

TL;DR

This study demonstrates high spin mixing conductance and interface transparency at the Co2Fe0.4Mn0.6Si Heusler alloy and Pt interface, enhancing spin-to-charge conversion efficiency for spintronic applications.

Contribution

It provides the first detailed investigation of spin pumping and inverse spin Hall effect in CFMS/Pt bilayers, revealing superior interface properties compared to other ferromagnet/heavy metal systems.

Findings

High spin mixing conductance of 1.77×10^20 m^-2

Interface transparency of 84%

Significant spin pumping confirmed by inverse spin Hall voltage

Abstract

Ferromagnetic materials exhibiting low magnetic damping ($\alpha$) and moderately high saturation magnetization are required from the viewpoints of generation, transmission and detection of spin wave. Since spin-to-charge conversion efficiency is another important parameter, high spin mixing conductance ($g_{r}^{\uparrow \downarrow}$) is the key for efficient spin-to-charge conversion. Full Heusler alloys e.g. $Co_2Fe_{0.4}Mn_{0.6}Si$ (CFMS), which are predicted to be 100$\%$ spin polarized, possess low $\alpha$. However, the $g_{r}^{\uparrow \downarrow}$ at the interface between CFMS and a paramagnet has not fully been understood. Here, we report the investigations of spin pumping and inverse spin Hall effect in $CFMS/Pt$ bilayers. Damping analysis indicates the presence of significant spin pumping at the interface of CFMS and Pt, which is also confirmed by the detection of inverse spin Hall voltage. We show that in CFMS/Pt the $g_{r}^{\uparrow \downarrow}$ (1.77$\times$10$^{20}$m$^{-2}$) and interface transparency (84$\%$) are higher compared to values reported for other ferromagnet/heavy metal systems.