Ricardo D. dos Reis, Luzeli M. da Silva, Adenilson O. dos Santos, Antonio Medina Neto, Lisandro P. Cardoso e Flavio C. G. Gandra

Journal of Alloys and Compounds – Volume: 582; Pages: 461–465; DOI: 10.1016/j.jallcom.2013.08.023
In this work we study the anisotropic magnetocaloric properties of ErGa2 and HoGa2 single-crystals. Both compounds present antiferromagnetic ordering below 10 K but with different easy axis as a result of the crystal field anisotropy. The single-crystal conventional MCE values are similar or in certain circumstances even larger than the results for the polycrystalline material. The anisotropic MCE was calculated by taking the difference of the entropy change of the easy and hard magnetization directions. For both compounds, the anisotropic variation of entropy is as large as the conventional entropy change obtained by sweeping the magnetic field up to 5 T. Particularly for ErGa2 an inverse MCE for a 3 T field oriented along the easy axis is obtained with similar magnitude of the 5 T MCE found for polycrystalline samples. The results show that by exploring anisotropic properties of the materials it is possible to obtain a significant MCE. From a technological point of view this can be an interesting alternative because the MCE is produced just by rotating the magnetic material under a constant magnetic field.