Inhomogeneous Magnetic Anisotropy in an Fe<sub>5-<i>x</i></sub>GeTe<sub>2</sub> Nanoflake Observed by Imaging.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40623161.
- Also identified by DOI 10.1021/acsnano.5c07836 and PMC identifier 12291590.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Few-layer flakes of ferromagnetic Fe<sub>5-<i>x</i></sub>GeTe<sub>2</sub> with <i>x</i> = 0.3 (F5GT) possess a <i>c</i>-axis magnetocrystalline anisotropy that is large enough below ∼200 K to outcompete the easy-plane shape anisotropy, yielding distinctive magnetic microstructures with out-of-plane (OOP) magnetizations. Using photoemission electron microscopy (PEEM) with magnetic contrast from X-ray magnetic circular dichroism (XMCD) to study a thermally demagnetized h-BN-protected nanoflake of F5GT at 110 K, we observe a micron-scale coexistence between domains with OOP magnetizations (∼70% areal fraction) and hitherto unknown domains in which in-plane (IP) magnetization components dominate (∼30% areal fraction). The regions with dominant IP magnetization components do not correlate with small variations of flake thickness (6-10 nm) and instead arise from local changes of magnetocrystalline anisotropy due to a hitherto unidentified chemical inhomogeneity that we suggest to be a higher concentration of Fe vacancies. Our observation of micron-scale inhomogeneity would likely be missed if imaging a single flake orientation and should affect the viability and performance of van der Waals (vdW) spintronic devices with F5GT electrodes.