Journal
JOURNAL OF ALLOYS AND COMPOUNDS
Volume 890, Issue -, Pages -Publisher
ELSEVIER SCIENCE SA
DOI: 10.1016/j.jallcom.2021.161849
Keywords
Magnetocaloric effect; Rare earth compound; Magnetic properties; Spin-ordering; Critical behavior
Categories
Funding
- Universidad del Pais Vasco UPV/EHU [GIU19/058]
- Russian Fund for Basic Research [20-03-00209-a]
- Department of Education of the Basque Government
Ask authors/readers for more resources
The study investigated the structural, magnetic, magnetocaloric, and thermal properties of seven intermetallic compounds, revealing complex magnetic transitions and magnetocaloric effects. Two of the compounds showed properties similar to rare earth-based high entropy alloys described in literature.
The structural, magnetic, magnetocaloric (MCE) and thermal properties of seven Fe2P-type Dy6(Fe,Mn)X2 (X=Sb, Bi, Te) intermetallics (space group P 6 over line 2 m, N 189, hP9) have been experimentally studied. They present a paramagnetic to ferromagnetic transition (in the range 129-370 K), followed, as temperature decreases, by a spin-reorientation one (from 52 to 170 K) and a ground magnetic state at 2 K with anti-ferromagnetic components. This state turns into a ferromagnetic state when a magnetic field is applied. The critical exponents beta,gamma,delta related to the PM-FM transition point to long range order interactions but in most compounds their values severely deviate from the Mean Field class, presenting an unconventional critical behavior, probably due to magnetocrystalline anisotropies. This magnetic complexity has the consequence that in every intermetallic three MCE effects arise: Two direct magnetocaloric effects (DMCE) with a table-like effect in between (from 40 K to more than 400 K), with moderate values of the magnetic entropy maxima (up to 6.9 J/kgK for 140 Delta H = 5 T, with the tableau in-between being around 4 J/kgK, for Dy6FeSb2 and Dy6FeSbTe). The calculation of the Thermal Average Entropy Change allows to place the properties of two compounds (Dy6FeSb2 and Dy6FeSbTe) close to other rare earth based high entropy alloys described in literature. The seven compounds present a relevant third MCE, inverse, below 25 K, with a value as high as 17.8 J/kgK (140 Delta H = 5 T) for Dy6FeSbTe. The maximum of the magnetic entropy change at the Curie tem-perature has been shown to scale with the critical exponents found and universal curves have been built. Finally, the thermal diffusivities in the range of the DMCE have been measured, with the result that they present good values (between 1 and 3 mm2/s) to be used in real magnetocaloric refrigeration systems. (c) 2021 The Author(s). Published by Elsevier B.V. CC_BY_NC_ND_4.0
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available