Ground-state ferrimagnetism and magneto-caloric effects in Nd2NiMnO6

Extending our earlier investigation of magnetic properties of Nd2NiMnO6, we show that it exhibits a magnetic transition below similar to 6 K to a ferrimagnetic state. This behavior is interpreted as arising from a long-range ordering of Nd moments antiferromagnetically coupled to the ferromagnetic Ni-Mn ordered moments. Due to the richness of its multiple magnetic transitions and the easily influenced magnetic state by the application of an external magnetic field, established in our earlier study, it has a remarkable inverse magneto-caloric effect (IMCE) at low temperatures (T < 50 K) together with a significant conventional magneto-caloric effect (CMCE) at the ferromagnetic ordering temperature (T-c similar to 200 K). IMCE and CMCE correspond to the antiferromagnetic arrangement of Nd and Ni-Mn sublattices and ferromagnetic ordering of Ni-Mn sublattices, respectively. Nd2NiMnO6 with its second order phase transition follows the universal behavior of Delta S-M(T); it also shows a power law dependency on the magnetic field as Delta S-M proportional to H-eta.