XPEEM and MFM Imaging of Ferroic Materials

Abstract

The authors describe and compare two complementary techniques that are habitually used to image ferromagnetic and ferroelectric materials with sub‐micron spatial resolutions (typically 50 nm, at best 10 nm). The first technique is variable‐temperature photoemission electron microscopy with magnetic/antiferromagnetic/polar contrast from circularly/linearly polarized incident X‐rays (XPEEM). The second technique is magnetic force microscopy (MFM). Focusing mainly on the authors’ own work, but not exclusively, published/unpublished XPEEM and MFM images of ferroic domains and complex magnetic textures (involving vortices and phase separation) are presented. Highlights include the use of two XPEEM images to create 2D vector maps of in‐plane (IP) magnetization, and the use of imaging to detect electrically driven local reversals of magnetization. The brief and simple descriptions of XPEEM and MFM should be useful for beginners seeking to employ these techniques in order to understand and harness ferroic materials.

Determination of optimal experimental conditions for accurate 3D reconstruction of the magnetization vector via XMCD-PEEM

“…Previous work has utilized X-ray magnetic circular dichroism PEEM (XMCD-PEEM) to reconstruct the spatially resolved magnetization vector, by combining images taken at different relative X-ray/sample orientations (Le Guyader et al, 2012;Ruiz-Go ´mez et al, 2018;Ghidini et al, 2022;Scholl et al, 2002;Chopdekar et al, 2013;Chmiel et al, 2018;Digernes et al, 2020). Here, we perform a detailed investigation of how the quality of the reconstructed 3D magnetization vector changes depending on the number of projections involved and their angular distribution.…”

Electronic structure orientation as a map of in-plane antiferroelectricity in β′-In 2 Se 3

“…Here, we show how PD-PEEM can image the AFE domains of β′-In 2 Se 3 on the nanoscale by directly measuring the energy-and polarization-dependent transition dipole moment (TDM). Previous PEEM studies have successfully imaged ferroelectric and ferromagnetic domains, but these studies have relied on x-ray and ultraviolet excitation to induce single-photon photoemission (PE), rather than probing optical transitions as in this work, and to date, those methods have not been used to resolve AFE domains (24)(25)(26)(27)(28). Despite having zero net permanent dipole, the small atomic distortions that give rise to the AFE nature of β′-In 2 Se 3 lead to electronic structure modifications that can be observed with PD-PEEM.…”

Electronic structure orientation as a map of in-plane antiferroelectricity in beta'- Indium(III) Selenide

“…In this paper, we show how PD-PEEM can image the AFE domains of β ′ -In 2 Se 3 on the nanoscale by directly measuring the energy-and polarization-dependent transition dipole moment. Previous PEEM studies have successfully imaged ferroelectric and ferromagnetic domains, but these studies have relied on X-ray and extreme UV excitation to access core levels and do not probe optical transitions as in this work [29][30][31][32]. Despite having zero net permanent dipole, the small atomic distortions that give rise to the AFE nature of β ′ -In 2 Se 3 lead to 1, fit to each pixel in the PD-PEEM data.…”