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Local probe evidence supporting altermagnetism in Co1/4NbSe2

J. N. Graham1,*,†, T. J. Hicken1,*,‡, Resham Babu Regmi2,3, M. Janoschek1,4, I. Mazin5,6, H. Luetkens1, N. J. Ghimire2,3, and Z. Guguchia1,§

  • *These authors contributed equally to the work.
  • †Contact author: jennifer.graham@fysik.lu.se
  • ‡Contact author: thomas.hicken@psi.ch
  • §Contact author: zurab.guguchia@psi.ch
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Phys. Rev. Research 8, 023361 – Published 30 June, 2026

DOI: https://doi.org/10.1103/6898-s17c

Abstract

Muon spin rotation (μ+SR) was used to investigate the magnetic properties of cobalt-intercalated 2H−NbSe2 (Co1/4NbSe2). Co1/4NbSe2 is predicted to be an altermagnet, and while neutron diffraction has proposed its magnetic structure, the microscopic details of this remain unclear. Therefore, a local probe investigation of the magnetism in Co1/4NbSe2 is essential. Our results reveal a sharp second-order transition to a full-volume-fraction, homogeneous magnetic order below TN=168K. The moments are aligned antiparallel along the c axis, consistent with neutron diffraction and altermagnetism. μ+SR reveals that the state remains stable under a c-axis magnetic field up to 0.78T, with magnetization measurements suggesting that this robust regime extends to at least 5 T. Within the time sensitivity of μ+SR, no precursor slow magnetic fluctuations were detected above TN, which is important for interpreting the band splitting in the paramagnetic state reported by photoemission studies.

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Phys. Rev. Research 8, 023361– Published 30 June, 2026
  • Received 8 December 2025
  • Accepted 26 May 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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