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Mapping metastable magnetic textures in (Fe0.5Co0.5)5GeTe2 with in situ Lorentz transmission electron microscopy

Reed Yalisove1,2, Hongrui Zhang1, Xiang Chen3, Fanhao Meng1,4, Jie Yao1,4, Robert Birgeneau3,4, Ramamoorthy Ramesh1, and Mary C. Scott1,2,*

  • *Contact author: mary.scott@berkeley.edu
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Phys. Rev. Materials 10, 074408 – Published 16 July, 2026

DOI: https://doi.org/10.1103/ml5v-s55s

Abstract

Topologically protected magnetic textures are a promising route to low-energy control of magnetism, but they are most often studied away from ambient conditions, typically at low temperatures and high magnetic fields. Here we use in situ Lorentz transmission electron microscopy with control of temperature and magnetic field to investigate the skyrmion metastability in (Fe0.5Co0.5)5GeTe2 (FCGT). By field-cooling FCGT in magnetic fields of different magnitude to different base temperatures and then removing the applied field, we create meta(stable) zero-field magnetic states. We use this method to build a phase diagram of the zero-field metastable spin structures in FCGT, which will be critical for selecting the desired topologically protected spin state for future studies to manipulate magnetism with stimuli such as electric current, electric field, mechanical strain, and more.

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Phys. Rev. Materials 10, 074408– Published 16 July, 2026
  • Received 26 January 2026
  • Accepted 20 April 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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