Strong Suppression of the Spin Hall Effect in the Spin Glass State

TL;DR

This study investigates how the spin Hall effect is suppressed in spin glass states of CuMnBi alloys, revealing a significant decrease below the spin glass temperature and proposing a model based on localized moments and conduction electron dynamics.

Contribution

It provides the first detailed measurement of spin Hall effects in spin glass metals and explains the suppression mechanism with a new theoretical model.

Findings

Spin Hall angle remains large above Tg but decreases sharply below Tg.

Suppression of the spin Hall effect correlates with the spin glass transition.

The proposed model links the suppression to the dynamics of localized magnetic moments.

Abstract

We have measured spin Hall effects in spin glass metals, CuMnBi alloys, with the spin absorption method in the lateral spin valve structure. Far above the spin glass temperature Tg where the magnetic moments of Mn impurities are randomly frozen, the spin Hall angle of CuMnBi ternary alloy is as large as that of CuBi binary alloy. Surprisingly, however, it starts to decrease at about 4Tg and becomes as little as 7 times smaller at 0.5Tg. A similar tendency was also observed in anomalous Hall effects in the ternary alloys. We propose an explanation in terms of a simple model considering the relative dynamics between the localized moment and the conduction electron spin.