Spin current at a magnetic junction as a probe of the Kondo state

TL;DR

This paper demonstrates that spin current measurements at a magnetic junction can serve as a direct probe of the Kondo state, revealing how the Kondo effect enhances spin transport and how it is affected by temperature and magnetic field.

Contribution

It introduces a novel approach to probe the Kondo state using spin current in a magnetic junction, supported by numerical renormalization group calculations.

Findings

Spin current is enhanced by the Kondo effect.

Spin current is suppressed by increasing temperature or magnetic field.

Spin transport can directly probe spin excitations in strongly correlated systems.

Abstract

We investigate the spin Seebeck effect and spin pumping in a junction between a ferromagnetic insulator and a magnetic impurity deposited on a normal metal. By the numerical renormalization group calculation, we show that spin current is enhanced by the Kondo effect. This spin current is suppressed by increase of the temperature or the magnetic field which is comparable with the Kondo temperature. Our results indicate that spin transport can be a direct probe of spin excitation in strongly correlated systems.