Magnetism, spintronics

Critical indices of phase transitions and magnetic entropy in PrDyFeCoB microwires

E. V. Dvoretskaya^ab, S. N. Kashin^a, R. A. Valeev^b, A. O. Kolmakov^a, M. V. Potapov^b, V. P. Piskorskii^b, R. B. Morgunov<sup>abc

a</sup> Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow region
^b All-Russian Scientific Research Institute of Aviation Materials, Moscow
^c Tambov State Technical University

Abstract: Microwires based on the PrDyFeCoB alloy in a field of 0–2 T are characterized by the presence of both positive and negative magnetocaloric effects (MCE) in the temperature ranges of 300–340 K and 200–240 K, respectively. The low-temperature negative MCE is caused by the transition between the ferromagnetic and spin-glass states of the alloy, and the high-temperature MCE occurs during the spin-reorientation transition as a result of the competition between the shape anisotropy and volume anisotropy. The maximum relative cooling power was RCP = 0.007 J/g in a field of 2 T. The values of the obtained critical coefficients indicate that at the transition temperature to the spin-glass state, the spin ordering is two-dimensional, described by the Ising model.

Keywords: polycrystalline microwires, rare earth alloys, magnetic entropy, magnetoelastic anisotropy, Curie temperature, magnetocaloric effect, critical indices.

Received: 04.08.2025
Revised: 05.08.2025
Accepted: 05.08.2025

DOI: 10.61011/FTT.2025.08.61327.222-25

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