Reduction of magnetic hysteresis loss in La0.5Pr0.5Fe11.4Si1.6Hx hydrides with large magnetocaloric effects

Magnetic properties and magnetocaloric effects (MCEs) have been investigated in hydrogenated La0.5Pr0.5Fe11.4Si1.6Hx (x=0, 0.9, and 1.6) compounds. It is found that the Curie temperature T-C can be tuned from 189 to 317 K by adjusting hydrogen content from 0 to 1.6. It is attractive that both thermal and magnetic hysteresis are remarkably reduced because of the weakness of the itinerant-electron metamagnetic transition after hydrogenation, while the large magnetic entropy change is retained. The maximal hysteresis loss at T-C decreases from 17.8 to 2.3 J/kg as x increases from 0 to 1.6. For the samples with x=0, 0.9, and 1.6, the maximal values of -Delta S are 26.3, 24.1, and 22.1 J/kg K at T-C, with efficient refrigeration capacities of 463, 366, and 351 J/kg for a field change of 0-5 T, respectively. Large reversible MCE and small hysteresis with considerable value of refrigeration capacity indicate the potentiality of La0.5Pr0.5Fe11.4Si1.6Hx hydrides as a candidate magnetic refrigerant around room temperature. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3374635]