Convergent-Beam EMCD: Benefits, Pitfalls, and Applications

TL;DR

This paper explores the use of convergent-beam electron energy-loss magnetic chiral dichroism (EMCD) to improve magnetic property analysis at the nanoscale, addressing signal-to-noise challenges and optimizing experimental parameters.

Contribution

It provides a theoretical analysis of convergent-beam EMCD, including detector positioning, convergence and collection angles, and offers guidelines for enhancing SNR and experimental effectiveness.

Findings

Convergent-beam EMCD can potentially improve SNR in magnetic measurements.

Optimal detector positioning and angles are crucial for maximizing EMCD signals.

Guidelines are proposed for experimental setup to achieve better results.

Abstract

Energy-loss magnetic chiral dichroism (EMCD) is a versatile method for studying magnetic properties on the nanoscale. However, the classical EMCD technique is notorious for its low signal to noise ratio (SNR). Here, we study the theoretical possibilities of using a convergent beam for EMCD. In particular, we study the influence of detector positioning as well as convergence and collection angles on the detectable EMCD signal. In addition, we analyze the expected SNR and give guidelines for achieving optimal EMCD results.