Magnetic properties and magnetocaloric effects (MCEs) of ternary intermetallic ErFeSi compound have been investigated in detail. It is found that ErFeSi exhibits a second-order magnetic transition from ferromagnetic to paramagnetic states at the Curie temperature TC = 22 K, which is quite close to the liquid hydrogen temperature (20.3 K). A thermomagnetic irreversibility between zero-field-cooling and field-cooling curves is observed below TC in low magnetic field, and it is attributed to the narrow domain wall pinning effect. For a magnetic field change of 5 T, the maximum values of magnetic entropy change (−ΔSM) and adiabatic temperature change (ΔTad) are 23.1 J/kg K and 5.7 K, respectively. Particularly, the values of −ΔSM and refrigerant capacity reach as high as 14.2 J/kg K and 130 J/kg under a magnetic field change of 2 T, respectively. The large MCE without hysteresis loss for relatively low magnetic field change suggests that ErFeSi compound could be a promising material for magnetic refrigeration of hydrogen liquefaction.

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