Spin pumping into a spin glass material

TL;DR

This paper theoretically explores how spin pumping from an insulating ferromagnet into spin glass materials varies with temperature, predicting a peak in the spin pumping signal near the spin glass transition due to slowing spin fluctuations.

Contribution

It introduces a theoretical framework combining spin glass dynamics with spin pumping to analyze temperature-dependent behavior near the transition.

Findings

A characteristic peak in spin pumping signal at the spin glass transition.

Spin fluctuations slow down as the system approaches spin freezing.

Theoretical prediction of temperature dependence of spin pumping in spin glasses.

Abstract

Spin pumping is a recently established means for generating a pure spin current, whereby spins are pumped from a magnet into the adjacent target material under the ferromagnetic resonance condition. We theoretically investigate the spin pumping from an insulating ferromagnet into spin glass materials. Combining a dynamic theory of spin glasses with the linear-response formulation of the spin pumping, we calculate temperature dependence of the spin pumping near the spin glass transition. The analysis predicts that a characteristic peak appears in the spin pumping signal, reflecting that the spin fluctuations slow down upon the onset of spin freezing.