Large reversible magnetocaloric effects in ErFeSi compound under low magnetic field change around liquid hydrogen temperature

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 T-C = 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 T-C 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 (-Delta S-M) and adiabatic temperature change (Delta T-ad) are 23.1 J/kg K and 5.7 K, respectively. Particularly, the values of -Delta S-M 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. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4794415]