Spin Accumulation at Ferromagnet/Non-magnetic Material Interfaces

TL;DR

This paper investigates spin accumulation at ferromagnet/non-magnetic interfaces, analyzing electric and spin profiles, and finds significant effects of screening and magnetic fields on spin accumulation.

Contribution

It introduces a comprehensive model including screening, spin scattering, and magnetic fields to analyze spin accumulation at interfaces, revealing larger effects than previously understood.

Findings

Spin accumulation in copper is much larger when chemical potential and magnetic field effects are included.

Screening significantly influences spin accumulation in the ferromagnet.

Both chemical potential differences and magnetic fields are crucial for accurate modeling.

Abstract

Many proposed and realized spintronic devices involve spin injection and accumulation at an interface between a ferromagnet and a non-magnetic material. We examine the electric field, voltage profile, charge distribution, spin fluxes, and spin accumulation at such an interface. We include the effects of both screening and spin scattering. We also include both the spin-dependent chemical potentials {\mu}_{\uparrow,\downarrow} and the effective magnetic field H* that is zero in equilibrium. For a Co/Cu interface, we find that the spin accumulation in the copper is an order of magnitude larger when both chemical potential and effective magnetic field are included. We also show that screening contributes to the spin accumulation in the ferromagnet; this contribution can be significant.