Induced Ge Spin Polarization at the Fe/Ge Interface

TL;DR

This study provides direct experimental evidence of induced spin polarization in germanium at the Fe/Ge interface, revealing antiparallel s and d magnetic moments aligned with Fe's magnetic moment.

Contribution

The paper presents the first direct experimental detection and detailed analysis of induced magnetic moments in Ge at the Fe/Ge interface using x-ray magnetic circular dichroism and resonant scattering.

Findings

Induced Ge magnetic moments are antiparallel to Fe moments.

Both s and d states in Ge are spin-polarized at the interface.

The magnitude of Ge moments is approximately 0.01 μB.

Abstract

We report direct experimental evidence showing induced magnetic moments on Ge at the interface in an Fe/Ge system. Details of the x-ray magnetic circular dichroism and resonant magnetic scattering at the Ge L edge demonstrate the presence of spin-polarized {\it s} states at the Fermi level, as well as {\it d} character moments at higher energy, which are both oriented antiparallel to the moment of the Fe layer. Use of the sum rules enables extraction of the L/S ratio, which is zero for the {\it s} part and $\sim0.5$ for the {\it d} component. These results are consistent with layer-resolved electronic structure calculations, which estimate the {\it s} and {\it d} components of the Ge moment are anti-parallel to the Fe {\it 3d} moment and have a magnitude of $\sim0.01 \mu_B$.