Reduction of hysteresis loss in LaFe11.7Si1.3H x hydrides with significant magnetocaloric effects

Abstract

Magnetic properties and magnetocaloric effects (MCEs) have been investigated in hydrogenated LaFe11.7 Si1.3Hx (x = 0, 1.37, and 2.07) compounds. It is found that the Curie temperature, TC, can be tuned from 192 to 338 K by adjusting the hydrogen content from 0 to 2.07. It is attractive that both thermal and magnetic hysteresis are remarkably reduced because of the weakness of the itinerant-electron metamagnetic transition after hydrogena- tion. The maximal hysteresis loss at TC decreases from 33.4 to 8.8 J/kg as x increases from 0 to 2.07. For the sam- ples with x = 0, 1.37, and 2.07, the maximal values of the isothermal magnetic entropy change, �S M, are 20.9, 15.1, and 15.83 J/kg K for the increasing field and 20.76 J/kg K, 14.53 J/kg K and 15.61 J/kg K for the decreasing field at TC, with efficient refrigeration capacities of 439, 330, and 304 J/kg for a field change of 0-5 T, respectively. Large re- versible MCE and small hysteresis with considerable refrig- eration capacity indicate the potential of LaFe11.7Si1.3Hx hydride as a candidate magnetic refrigerant around room temperature.