Exchange magnetic field torques in YIG/Pt bilayers observed by the spin-Hall magnetoresistance

TL;DR

This study measures the effective magnetic field torques in YIG/Pt bilayers using spin-Hall magnetoresistance, revealing key parameters like spin diffusion length and spin-mixing conductance components.

Contribution

It provides experimental quantification of exchange magnetic field torques and spin-mixing conductance in YIG/Pt bilayers through SMR measurements, advancing understanding of spin transport.

Findings

Spin diffusion length of Pt is 1.1±0.3 nm.

Real part of spin-mixing conductance is (7±3)×10^{14} Ω^{-1}m^{-2}.

Imaginary part of spin-mixing conductance is (5±3)×10^{13} Ω^{-1}m^{-2}.

Abstract

The effective field torque of an yttrium-iron-garnet film on the spin accumulation in an attached Pt film is measured by the spin-Hall magnetoresistance (SMR). As a result, the magnetization direction of a ferromagnetic insulating layer can be measured electrically. Experimental transverse and longitudinal resistances are well described by the theoretical model of SMR in terms of the direct and inverse spin-Hall effect, for different Pt thicknesses [3, 4, 8 and 35nm]. Adopting a spin-Hall angle of Pt $\theta_{SH}=0.08$, we obtain the spin diffusion length of Pt ($\lambda=1.1\pm0.3$nm) as well as the real ($G_r=(7\pm3)\times10^{14}\Omega^{-1}$m$^{-2}$) and imaginary part ($G_i=(5\pm3)\times10^{13}\Omega^{-1}$m$^{-2}$) of the spin-mixing conductance and their ratio ($G_r/G_i=16\pm4$).