Spin Currents in Metallic Nanostructures; Explicit Calculations

TL;DR

This paper presents a method using the Kubo formalism to explicitly calculate spin currents generated by spin precession in ultrathin ferromagnetic films on metallic substrates, highlighting its role in spin dynamics.

Contribution

It introduces a novel approach for explicit calculation of spin currents in nanoscale systems using the Kubo formalism, advancing understanding of spin pumping effects.

Findings

Explicit calculation of spin currents in a model system

Identification of spatial variation of spin currents

Insights into damping mechanisms in ultrathin ferromagnets

Abstract

In ultrathin ferromagnets deposited on metallic substrates, excitation of precessional motion of the spins produces a spin current in the substrate that transports angular momentum out of the film. This phenomenon is referred to as spin pumping, and is a source of damping of the spin motion. Spin pumping enters importantly in the description of spin dynamics in other nanoscale and subnanoscale systems as well. In this paper, we present an approach based on the Kubo formalism that allows the explicit calculation of this spin current and its spatial variation. We use the formalism to explore features of the spin current generated by spin motions in a simple model system.