An in-plane magnetic chiral dichroism approach for measurement of intrinsic magnetic signals using transmitted electrons

Dongsheng Song,Jing Zhu,Rafal E Dunin-Borkowski,Wenting Huang,András Kovács,Amir H Tavabi,Ján Rusz,Gunther Richter,Zi-An Li

doi:10.1038/ncomms15348

Abstract

Electron energy-loss magnetic chiral dichroism is a powerful technique that allows the local magnetic properties of materials to be measured quantitatively with close-to-atomic spatial resolution and element specificity in the transmission electron microscope. Until now, the technique has been restricted to measurements of the magnetic circular dichroism signal in the electron beam direction. However, the intrinsic magnetization directions of thin samples are often oriented in the specimen plane, especially when they are examined in magnetic-field-free conditions in the transmission electron microscope. Here, we introduce an approach that allows in-plane magnetic signals to be measured using electron magnetic chiral dichroism by selecting a specific diffraction geometry. We compare experimental results recorded from a cobalt nanoplate with simulations to demonstrate that an electron magnetic chiral dichroism signal originating from in-plane magnetization can be detected successfully.

Highlights

Electron energy-loss magnetic chiral dichroism is a powerful technique that allows the local magnetic properties of materials to be measured quantitatively with close-to-atomic spatial resolution and element specificity in the transmission electron microscope
Since the first demonstration by Schattschneider et al.[1] in 2006 that electron magnetic circular dichroism (EMCD) signal can be detected using high-energy electrons in the transmission electron microscope (TEM), theoretical and experimental progress have led to improvements in spatial resolution and signal-to-noise ratio[2,3,4,5], an improved fundamental understanding of the technique[6,7,8,9,10] and quantitative measurements of spin and orbital magnetic moments with both element and site specificity[11,12,13,14]
Until now the technique has only been able to detect magnetic signals in the out-of-plane direction, in contrast to magnetic characterization methods based on phase contrast in the TEM such as Lorentz microscopy, differential phase-contrast imaging and off-axis electron holography that are sensitive to in-plane components of the magnetic flux density within and around the sample[16,17]

Summary

Introduction

Electron energy-loss magnetic chiral dichroism is a powerful technique that allows the local magnetic properties of materials to be measured quantitatively with close-to-atomic spatial resolution and element specificity in the transmission electron microscope. Since the first demonstration by Schattschneider et al.[1] in 2006 that electron magnetic circular dichroism (EMCD) signal can be detected using high-energy electrons in the transmission electron microscope (TEM), theoretical and experimental progress have led to improvements in spatial resolution and signal-to-noise ratio[2,3,4,5], an improved fundamental understanding of the technique[6,7,8,9,10] and quantitative measurements of spin and orbital magnetic moments with both element and site specificity[11,12,13,14]. We use the approach to measure in-plane magnetic signals from a single crystalline Co sample in Lorentz mode, thereby demonstrating a new powerful working principle for the technique

Methods

Results

Conclusion