Article YbCo2: Large magnetic entropy change per volume in Yb-based metallic magnetic refrigerants for sub-Kelvin temperature

Yasuyuki Shimura ORCID ; Ryoma Yokoo ORCID ; Kanta Watanabe ORCID ; Hiroto Furuie ; Naohito Tsujii SAMURAI ORCID ; Kazunori Umeo ORCID ; Takahiro Onimaru ORCID

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Yasuyuki Shimura, Ryoma Yokoo, Kanta Watanabe, Hiroto Furuie, Naohito Tsujii, Kazunori Umeo, Takahiro Onimaru. YbCo2: Large magnetic entropy change per volume in Yb-based metallic magnetic refrigerants for sub-Kelvin temperature. Applied Physics Letters. 2025, 127 (10), 102403. https://doi.org/10.1063/5.0287094

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(abstract)

A Yb-based intermetallic compound YbCo2 exhibiting a magnetic-field-induced order is known to show a giant specific heat divided by temperature, C/T ~ 6.5 J/K2 mol, around 0.3 K. We investigate the potential of this substance as the magnetic refrigerants by measuring the thermodynamic properties down to 0.1 K. The entropy change per volume by applying magnetic field of 3 T is found to be -Delta_S_M ~ 0.15 J/K cm3 around 1K. This value is particularly large in the Yb-based metallic magnetic refrigerants to provide the sub-Kelvin temperature. In addition,
we demonstrate that a 2.2 g sample is cooled down to 0.26 K by the adiabatic demagnetization refrigeration from 1.8 K and 12 T. This cooling performance is attributed to the ground state, at zero field, locating around the boundary between the field-induced ordered phase and the paramagnetic one. Our study clarifies the utility of the sub-Kelvin magnetic refrigerants, which combine the large Delta_S_M and the high thermal conductivity of metal.

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  • In Copyright

    This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Yasuyuki Shimura, Ryoma Yokoo, Kanta Watanabe, Hiroto Furuie, Naohito Tsujii, Kazunori Umeo, Takahiro Onimaru; YbCo2: Large magnetic entropy change per volume in Yb-based metallic magnetic refrigerants for sub-Kelvin temperature. Appl. Phys. Lett. 8 September 2025; 127 (10): 102403 and may be found at https://doi.org/10.1063/5.0287094.

Keyword: YbCo2, Yb compounds, Magnetic entropy, Heavy Fermion

Date published: 2025-09-08

Publisher: AIP Publishing

Journal:

  • Applied Physics Letters (ISSN: 00036951) vol. 127 issue. 10 102403

Funding:

  • Fusion Oriented REsearch for disruptive Science and Technology JPMJFR2233
  • Japan Society for the Promotion of Science JP22K03529
  • Japan Society for the Promotion of Science 23H04866
  • Japan Society for the Promotion of Science 23H04870
  • Japan Society for the Promotion of Science and 24K21692
  • Kyoto Technoscience Center 8
  • Mazda Foundation 21KK-191

Manuscript type: Author's version (Accepted manuscript)

MDR DOI: https://doi.org/10.48505/nims.5939

First published URL: https://doi.org/10.1063/5.0287094

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Updated at: 2025-11-28 16:30:19 +0900

Published on MDR: 2025-11-28 16:21:59 +0900

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