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  • Letter
  • Open Access

Magnetic phase diagram of YbRh2Si2: The influence of hyperfine interactions

J. Knapp1,2,*, L. V. Levitin1,†, J. Nyéki1, B. Cowan1, M. Brando2, C. Geibel2, K. Kliemt3, C. Krellner3, and J. Saunders1,‡

  • *Contact author: jan.knapp@rhul.ac.uk
  • †Contact author: l.v.levitin@rhul.ac.uk
  • ‡Contact author: j.saunders@rhul.ac.uk
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Phys. Rev. Research 7, L042043 – Published 25 November, 2025

DOI: https://doi.org/10.1103/yl3t-1gj5

Abstract

We report the determination of the magnetic phase diagram of the heavy fermion metal YbRh2Si2 in magnetic fields up to 70 mT applied perpendicular to the crystallographic c axis. By a combination of heat capacity, magnetocaloric, and magnetoresistance measurements, we map two antiferromagnetic phases: the electronic AFM1 below 70 mK and electronuclear AFM2 below 1.5 mK. The measurements extend into the microkelvin regime to explore the quantum phase transitions in this system. We demonstrate how the hyperfine interaction significantly modifies the phase diagram and the putative field-tuned quantum critical point. The determination of the rich magnetic properties of YbRh2Si2 is essential to understanding the interplay of the two magnetic orders and superconductivity in this compound.

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Phys. Rev. Research 7, L042043– Published 25 November, 2025
  • Received 31 January 2025
  • Revised 5 May 2025
  • Accepted 2 October 2025
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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. Open access publication funded by Max Planck Society.

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