Magnetocaloric effect of rare earth mono-nitrides, TbN and HoN

Rare earth (RE) mono-nitrides, TbN and HoN, were synthesized by the carbothermic reduction method. Their magnetocaloric effect (MCE) was evaluated by calculating the magnetic entropy changes, ΔS, from the magnetization data sets measured at various temperatures and applied fields. The ΔS value of HoN was highest at 18 K and larger than that of DyNi2 reported as the candidate material of magnetic refrigerant for hydrogen liquefaction. The ΔS value of TbN was highest at 44 K and comparable with that of (DyHo)Al2 with the transition temperature of 46 K