Element specific characterization of heterogeneous magnetism in (Ga,Fe)N films

TL;DR

This study uses x-ray spectroscopy and microscopy to analyze the distribution and magnetic properties of Fe in (Ga,Fe)N films, revealing Fe-rich nanoregions and linking high-temperature ferromagnetism to Fe(3d) states.

Contribution

It provides a detailed element-specific characterization of magnetic behavior and nanostructure formation in (Ga,Fe)N films using advanced spectroscopic techniques.

Findings

Fe-rich nanoregions form near the surface.

High-temperature ferromagnetism is linked to Fe(3d) states.

N(2p) states exhibit significant spin polarization.

Abstract

We employ x-ray spectroscopy to characterize the distribution and magnetism of particular alloy constituents in (Ga,Fe)N films grown by metal organic vapor phase epitaxy. Furthermore, photoelectron microscopy gives direct evidence for the aggregation of Fe ions, leading to the formation of Fe-rich nanoregions adjacent to the samples surface. A sizable x-ray magnetic circular dichroism (XMCD) signal at the Fe L-edges in remanence and at moderate magnetic fields at 300 K links the high temperature ferromagnetism with the Fe(3d) states. The XMCD response at the N K-edge highlights that the N(2p) states carry considerable spin polarization. We conclude that FeN{\delta} nanocrystals, with \delta > 0.25, stabilize the ferromagnetic response of the films.