Large cryogenic magnetocaloric effect of the Laves-phase Ho1-xDyxAl2 compounds within liquid hydrogen temperature range

In this work, a large cryogenic magnetocaloric effect was achieved in laves-phase Ho1-xDyxAl2 (x = 0, 0.25, 0.5, 0.75, 1) compounds with MgCu2-type cubic structure (space group Fd3m). The Ho1-xDyxAl2 compounds undergo the second order magnetic transition. The maximum magnetic entropy changes with the mu 0 Delta H = 5 T of the Ho1-xDyxAl2 bulks are 27.5, 25.2, 22.2, 20.8, and 19.8 J kg- 1 K- 1 respectively. The spherical particles of Ho1- xDyxAl2 were prepared by electrode induction melting gas atomization (EIGA). The gas-atomized particles exhibit high sphericity. Additionally, the Curie temperature and the order of magnetic phase transition of the spherical particles are consistent with those of bulk counterparts. The maximum magnetic entropy with mu 0 Delta H = 5 T of Ho0.5Dy0.5Al2 spherical particles reaches 17.20 J kg- 1 K- 1. The excellent magnetocaloric properties of the bulks and spherical particles facilitate the production of magnetic refrigerants needed for developing magnetic refrigerators operating within the liquid hydrogen temperature range.