Quantitative analysis of magnetic spin and orbital moments from an oxidized iron (1 1 0) surface using electron magnetic circular dichroism

TL;DR

This study uses electron magnetic circular dichroism (EMCD) via TEM to analyze how nanoscale oxide layers on iron surfaces influence local magnetic spin and orbital moments, revealing angle-dependent magnetic behavior.

Contribution

It demonstrates a method to locally probe and quantify the magnetic orbital to spin ratio in nanoscale oxide layers on iron surfaces using EMCD.

Findings

Magnetic orbital to spin ratio varies with scattering angle.

Oxide layers can exhibit enhanced orbital to spin moments.

Spatially resolved EMCD reveals nanoscale magnetic heterogeneity.

Abstract

Understanding the ramifications of reduced crystalline symmetry on magnetic behavior is a critical step in improving our understanding of nanoscale and interfacial magnetism. However, investigations of such effects are often controversial largely due to the challenges inherent in directly correlating nanoscale stoichiometry and structure to magnetic behavior. Here, we describe how to use Transmission Electron Microscope (TEM) to obtain Electron Magnetic Circular Dichroism (EMCD) signals as a function of scattering angle to locally probe the magnetic behavior of thin oxide layers grown on an Fe (1 1 0) surface. Experiments and simulations both reveal a strong dependence of the magnetic orbital to spin ratio on its scattering vector in reciprocal space. We exploit this variation to extract the magnetic properties of the oxide cladding layer, showing that it locally may exhibit an enhanced orbital to spin moment ratio. This finding is supported here by both spatially and angularly resolved EMCD measurements, opening up the way for compelling investigations into how magnetic properties are affected by nanoscale features.