Spin transport in half-metallic ferromagnets

TL;DR

This paper theoretically examines how spin Hall conductivity in half-metallic ferromagnets varies with temperature, highlighting the roles of electron-magnon interactions and scattering mechanisms, and suggests its use in probing minority-spin states.

Contribution

It introduces a theoretical framework for understanding temperature-dependent spin Hall conductivity in half-metallic ferromagnets, emphasizing the impact of electron-magnon interactions.

Findings

Spin Hall conductivity is proportional to T^{3/2}.

Electron-magnon interactions induce finite density of states in the energy gap.

Spin Hall conductivity is sensitive to temperature variations.

Abstract

We theoretically investigate spin transport in half-metallic ferromagnets at finite temperatures. The side-jump and skew-scattering contributions to spin Hall conductivity are derived using the Kubo formula. The electron-magnon interaction causes a finite density of states in the energy gap of the minority-spin band and induces spin Hall conductivity. We show that spin Hall conductivity is proportional to $T^{3/2}$, with $T$ being temperature and is sensitive to $T$. We propose that spin Hall conductivity may be a tool to study the minority-spin state.