Influence of antisite disorders on the magnetic properties of double perovskite Nd2NiMnO6

The structural and magnetic properties of polycrystalline Nd2NiMnO6 (NNMO) synthesized by solid state reaction method have been investigated. Rietveld refinement of Powder X-Ray diffraction data suggests that NNMO compound crystallizes in monoclinic phase with space group P2(1)/n. Magnetic measurements reveal an additional magnetic transition T-C' similar to 85 K due to to Ni3+-O-Mn3+ antiferromagnetic super exchange interaction along with ferromagnetic transition similar to 196 K in M-T curve, leading to anti ferromagnetic interactions in this compound. High sintering temperature (upto 1100 degrees C) leads to the formation of antisite disorders and antiferromagnetic antiphase boundaries in the present sample. The magnetic hysteresis measurements show ferromagnetic behavior with low saturation magnetization value (similar to 2 mu(B)/f.u.) than the theoretical spin-only value (5 mu(B)/f.u.) of Ni/Mn ions. Hence, antisite disorders diminish the long range ferromagnetic ordering and also affect the magnetic properties of this compound. Exchange bias behavior has been observed in the hysteresis loops when the sample was field cooled from 300 K to 5 K. Exchange coupling between the ferromagnetic moments and anti ferromagnetic antiphase boundaries is responsible for the observation of exchange bias in the present system. (C) 2016 Elsevier Ltd. All rights reserved.