Large reversible magnetocaloric effect caused by two successive magnetic transitions in ErGa compound

Intermetallic compound ErGa exhibits two successive magnetic transitions: spin-reorientation transition at T-SR=15 K and ferromagnetic-paramagnetic transition at T-C=30 K. Both transitions contribute greatly to the magnetic entropy change (Delta S-M), each yielding a significant peak on their Delta S-M-T curve and thus a considerable value of refrigerant capacity (RC) without hysteresis loss. For a magnetic field change of 5 T, the maximal values of -Delta S-M are 21.3 J/kg K at T-C and 16.5 J/kg K at T-SR, with an RC value of 494 J/kg. Large reversible magnetocaloric effect and RC indicate the potentiality of ErGa as a candidate magnetic refrigerant at low temperatures. (C) 2009 American Institute of Physics. [doi:10.1063/1.3233925]