Structure, magnetism and magnetocaloric effect of perovskite oxides Gd_1.8Ce_0.2NiMnO₆.

In this work, polycrystalline sample of perovskite oxide Gd_1.8Ce_0.2NiMn_O6 was prepared by the conventional high-temperature solid-phase reaction method, and the magnetic properties of the sample was investigated. Gd_1.8Ce_0.2NiMn_O6 shows Griffiths-like phase in the temperature region of paramagnetic-ferromagnetic phase transition process. The magnetic moment undergoes a process of transformation from disorder to order, which laying the foundation for further research on the magnetothermal effect of this material. Gd_1.8Ce_0.2NiMn_O6 showed a significant magnetic entropy change near the Curie temperature at the magnetic field of 7 T, which reaches 3.13 J·kg^-1·K ^-1, and its relative cooling power（RCP）reaches 231.1 J/kg. Therefore, the research results of this article prove that Ce doped Gd based powders have good application prospects in the field of magnetic refrigeration.