Authors: Y. Mao, J.G. Parsons, J.S. McCloy
Affilation: University of Texas-Pan American, United States
Pages: 707 - 710
Keywords: double perovskite, nanoparticle, DC magnetization, magnetic hysteresis, AC susceptibility
Double perovskite oxides with the general formula AA’BB’O6 (where A and A’ are rare earth or alkaline earth metals, and B and B’ are d-block transition metals) display a wide variety of interesting physical properties with composition variations. Recently, nanostructures of metal oxides, metals and carbon have been investigated as emerging materials because they exhibit interesting physical properties which are different from those of their bulk and thin film counterparts. Here, La2BMnO6 (B = Ni and Co) nanoparticles with average particle size of 50 nm were synthesized using a facile, environmentally friendly, scalable molten-salt synthetic process at 700 °C in air. Their structural and morphological properties were characterized by x-ray diffraction and transmission electron microscopy. Magnetic properties evaluated using DC magnetic M-T and M-H, and AC magnetic susceptibility versus frequency, temperature and field indicate that they possess very different magnetic behaviors. The magnetization curve shows a paramagnetic-ferromagnetic transition at TC ~275 and 220 K for La2NiMnO6 and La2CoMnO6 nanoparticles, respectively, which are almost unchanged from their bulk and thin film counterparts. AC susceptibility revealed that the La2CoMnO6 had a single magnetic transition indicative of Co2+-O2--Mn4+ ordering, whereas the La2NiMnO6 showed more complex magnetic behavior suggesting a re-entrant spin glass.