Magnetic properties of double perovskite La2BMnO6 (B = Ni or Co) nanoparticles

Double perovskite La2BMnO6 (B = Ni and Co) nanoparticles with average particle size of similar to 50 nm were synthesized using a facile, environmentally friendly, and scalable molten-salt reaction at 700 degrees C in air. Their structural and morphological properties were characterized by X-ray diffraction and transmission electron microscopy. Their magnetic properties were evaluated and compared using dc magnetic M-T and M-H, and ac magnetic susceptibility versus frequency, temperature, and field for the first time. The dc magnetization curves show paramagnetic-ferromagnetic transitions at T-C similar to 275 and 220 K for La2NiMnO6 (LNMO) and La2CoMnO6 (LCMO) nanoparticles, respectively. ac susceptibility revealed that the LCMO nanoparticles had a single magnetic transition indicative of Co2+-O2--Mn4+ ordering, whereas the LNMO nanoparticles showed more complex magnetic behaviors suggesting a re-entrant spin glass.