Magnetocaloric Effect of Rare Earth Nitrides

Dy_0.5Ho_0.5N, Tb_0.5Dy_0.5N, and Tb_0.5Gd_0.5N were synthesized using two methods, carbothermic reduction and hot isostatic pressing, and their magnetocaloric effects were evaluated. The magnetization and specific heat of the nitrides were measured, and the magnetic entropy change DeltaS, adiabatic temperature change DeltaT and relative cooling power RCP were calculated. Values of RCP for the rare earth nitrides were larger than those of intermetallic compounds so far reported. The rare earth nitrides are promising magnetic refrigerant materials for hydrogen liquefaction systems working below liquid nitrogen temperatures.