Current-driven spin injection from a probe to a ferromagnetic film

TL;DR

This paper analyzes how current-driven spin injection from a probe affects electron spin polarization in a ferromagnetic film, highlighting key parameters and the potential for inverse spin population at certain distances.

Contribution

It provides a detailed calculation of spin polarization distribution considering probe parameters and identifies conditions for inverse spin population in ferromagnetic films.

Findings

Spin polarization depends mainly on current density and probe material polarization.

Weak influence of probe diameter relative to spin diffusion length.

Inverse spin subband population can be achieved near the probe boundary.

Abstract

The distribution is calculated of the electron spin polarization under current-driven spin injection from a probe to a ferromagnetic film. It is shown that the main parameters determining difference of the spin polarization from the equilibrium value are the current density and the spin polarization of the probe material, while the relation between the probe diameter and the spin diffusion length influences the result very weakly, to a certain extent. A possibility is shown of reaching inverse population of the spin subbands at distances from the probe boundary comparable with the spin diffusion length.