High magnetic-refrigeration performance of plate-shaped La0.5Pr0.5Fe11.4Si1.6 hydrides sintered in high-pressure H2 atmosphere

La(Fe, Si)13 hydride is regarded as one of the most promising room-temperature refrigerants. However, to use the alloys in an active magnetic regenerator machine, it is vital to prepare thin refrigerants. In this work, a high H2 gas pressure of 50 MPa was employed to suppress the desorption of hydrogen atoms during the sintering process of plate-shaped La0.5Pr0.5Fe11.4Si1.6 hydrides. At 330 K, a high-density sintered thin plate shows a large magnetic-entropy change ΔSm of 15.5 J/kg K (106 mJ/cm3 K) for a field change of 2 T. The volumetric ΔSm is almost twice as large as that of bonded La(Fe,Si)13 hydrides. Favorably, hysteresis is almost absent due to the existence of micropores with a porosity of 0.69% which has been analyzed with high-resolution X-ray microtomography.