Thermally excited spin-current in metals with embedded ferromagnetic nanoclusters

TL;DR

This paper demonstrates that metals with embedded ferromagnetic nanoclusters can generate a thermally excited spin-current when subjected to a magnetic field and temperature gradient, explained by electron-hole symmetry breaking.

Contribution

It introduces a theoretical explanation for thermally excited spin-currents in such metals, linking spin-current generation to electron-hole symmetry breaking and magneto-thermopower.

Findings

The theory explains the observed giant magneto-thermopower.

Spin-current magnitude correlates with magnetic polarization.

The model aligns with recent experimental results on Co clusters in copper.

Abstract

We show that a thermally excited spin-current naturally appears in metals with embedded ferromagnetic nanoclusters. When such materials are subjected to a magnetic field, a spin current can be generated by a temperature gradient across the sample as a signature of electron-hole symmetry breaking in a metal due to the electron spin-flip scattering from polarised magnetic moments. Such a spin current can be observed via a giant magneto-thermopower which tracks the polarisation state of the magnetic subsystem and is proportional to the magnetoresistance. Our theory explains the recent experiment on Co clusters in copper by S. Serrano-Guisan \textit{et al} [Nature Materials AOP, doi:10.1038/nmat1713 (2006)]