Influence of plural scattering on the quantitative determination of spin and orbital moments in electron magnetic circular dichroism measurements

TL;DR

This paper investigates how plural scattering affects the accuracy of spin and orbital magnetic moment measurements in EMCD experiments, proposing a correction method to improve quantitative analysis.

Contribution

It introduces an equation modeling plural scattering influence and demonstrates how to remove it via spectral deconvolution in EMCD measurements.

Findings

Plural scattering significantly impacts the $m_L/m_S$ ratio.

Deconvolution of spectra can correct for plural scattering effects.

Corrected $m_L/m_S$ ratio for bcc-Fe is 0.04 after removal.

Abstract

Recent quantitative measurements of the orbital to spin magnetic moment ratio $m_L/m_S$ in electron magnetic circular dichroism (EMCD) experiments have given a $m_L/m_S$ ratio that is larger than commonly accepted values. We demonstrate here that plural scattering may noticeably influence the $m_L/m_S$ ratio. An equation is derived which describes its influence as a function of the spectral integrals of the plasmon scattering region and zero-loss peak. The influence of the electron-plasmon scattering can be removed when electron energy-loss spectra of the ionization edge are deconvoluted by the low-loss signal. For a bcc-Fe sample we obtain $m_L/m_S=0.04$ after plasmon removal. We conclude that the plural scattering should be considered when extracting quantitative information from EMCD measurements.