Journal article Room-temperature in-plane ferromagnetism in Co-substituted Fe5GeTe2 investigated by magnetic x-ray spectroscopy and microscopy

Emily Heppell ; Ryuji Fujita ; Gautam Gurung ; Jheng-Cyuan Lin ; Andrew F May ; Michael Foerster ; M Waqas Khaliq ; Miguel Angel Niño ; Manuel Valvidares ; Javier Herrero-Martín ; Pierluigi Gargiani ; Kenji Watanabe SAMURAI ORCID (National Institute for Materials Science) ; Takashi Taniguchi SAMURAI ORCID (National Institute for Materials Science) ; Dirk Backes ; Gerrit van der Laan ; Thorsten Hesjedal

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Emily Heppell, Ryuji Fujita, Gautam Gurung, Jheng-Cyuan Lin, Andrew F May, Michael Foerster, M Waqas Khaliq, Miguel Angel Niño, Manuel Valvidares, Javier Herrero-Martín, Pierluigi Gargiani, Kenji Watanabe, Takashi Taniguchi, Dirk Backes, Gerrit van der Laan, Thorsten Hesjedal. Room-temperature in-plane ferromagnetism in Co-substituted Fe5GeTe2 investigated by magnetic x-ray spectroscopy and microscopy. 2D Materials. 2025, 12 (2), 025001. https://doi.org/10.1088/2053-1583/ada040

Description:

(abstract)

The exploration of two-dimensional (2D) van der Waals ferromagnets has revealed intriguing magnetic properties with significant potential for spintronics applications. In this study, we examine the magnetic properties of Co-doped Fe5GeTe2 using X- ray photoemission electron microscopy (XPEEM) and X-ray magnetic circular dichroism (XMCD), complemented by density functional theory (DFT) calculations. Our XPEEM measurements reveal that the Curie temperature (TC) of a bilayer of (Co0.25Fe0.75)5GeTe2 reaches ∼300K, a notable enhancement over other 2D ferromagnets in the ultra- thin limit. Interestingly, the TC shows minimal dependence on film thickness (bulk TC ≈ 310 K), aligning with the observed in-plane magnetic anisotropy and robust in- plane exchange coupling. XMCD measurements indicate that the spin moments for both Fe and Co are significantly reduced compared to the theoretical values. These in- sights provide a deeper understanding of the magnetic behavior of Co-doped Fe5GeTe2 and highlight its potential for stable, high-temperature ferromagnetic applications in 2D materials.

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Keyword: room-temperature ferromagnetism
, Fe5GeTe2
, 2D ferromagnets

Date published: 2025-04-01

Publisher: IOP Publishing

Journal:

  • 2D Materials (ISSN: 20531583) vol. 12 issue. 2 025001

Funding:

  • World Premier International Research Center Initiative
  • Oxford-ShanghaiTech collaboration project
  • Basic Energy Sciences Materials Sciences and Engineering Division
  • Engineering and Physical Sciences Research Council EP/X015556/1
  • Diamond Light Source Materials Characterisation Laboratory
  • ALBA Synchrotron 2022097164
  • Japan Society for the Promotion of Science 21H05233

Manuscript type: Publisher's version (Version of record)

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First published URL: https://doi.org/10.1088/2053-1583/ada040

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Updated at: 2026-05-25 09:01:08 +0900

Published on MDR: 2026-05-25 10:29:19 +0900

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