Direct Evidence for Suppression of the Kondo Effect due to Pure Spin Current

TL;DR

This study provides direct experimental evidence that pure spin currents can suppress the Kondo effect in magnetic alloys, revealing the interplay between spin accumulation and many-body electron correlations.

Contribution

It demonstrates the suppression of the Kondo singlet by pure spin currents using non-local spin valve structures with highly spin polarized electrodes.

Findings

Spin signals decrease sharply with temperature below TK.

Spin diffusion length increases with spin accumulation.

Kondo singlet cannot survive large spin accumulation.

Abstract

We study the effect of a pure spin current on the Kondo singlet in a diluted magnetic alloy using non-local lateral spin valve structures with highly spin polarized Co2FeSi electrodes. Temperature dependence of the non-local spin signals shows a sharp reduction with decreasing temperature, followed by a plateau corresponding to the low temperature Fermi liquid regime below the Kondo temperature (TK). The spin diffusion length of the Kondo alloy is found to increase with the evolution of spin accumulation. The results are in agreement with the intuitive description that the Kondo singlet cannot survive any more in sufficiently large spin accumulation even below TK.