Spin-signal propagation in time-dependent noncollinear spin transport

TL;DR

This paper demonstrates that time-dependent noncollinear spin transport exhibits wave-like behavior, enabling the extraction of a finite spin-signal propagation velocity through numerical analysis of spin current dynamics across GHz to THz frequencies.

Contribution

It introduces a macroscopic analysis revealing wave-like characteristics in spin transport and quantifies the finite propagation velocity in noncollinear, time-dependent scenarios.

Findings

Spin transport shows wave-like behavior.

Finite spin-signal propagation velocity is identified.

Numerical simulations cover GHz to THz frequencies.

Abstract

Using a macroscopic analysis, we show that time-dependent noncollinear spin transport possesses a wavelike character. This leads to modifications of pure spin-diffusion dynamics and allows one to extract a finite spin-signal propagation velocity. We numerically study the dynamics of a pure spin current pumped into a nonmagnetic layer for precession frequencies ranging from GHz to THz.