Magnetocaloric effects of binary rare earth mononitrides, Gd x Tb1−x N and Tb x Ho1−x N

Abstract: We have synthesized Gd x Tb1−x N and Tb x Ho1−x N (x =0, 0.25, 0.5, 0.75 and 1) by the carbothermic reduction performed in a nitrogen gas stream. GdN and TbN have been completely miscible with each other as well as TbN and HoN. As x was changed from 0 to 1, the Curie temperature increased monotonously from 18.5 to 43.8K for Tb x Ho1−x N and from 43.8 to 61.2K for Gd x Tb1−x N. The magnetocaloric effects have been evaluated by calculating the magnetic entropy changes from the magnetization data sets measured at different applied fields and temperatures. In any composition x, the magnetocaloric effects of Gd x Tb1−x N and Tb x Ho1−x N are larger than those of Gd x Dy1−x N. Therefore, Gd x Tb1−x N and Tb x Ho1−x N are promising magnetic refrigerant materials for hydrogen liquefying system working below liquid nitrogen temperature. [Copyright &y& Elsevier]