Mechanochemical Synthesis of Soft Ferromagnetic Perovskite Lanthanum Strontium Manganite (La0.6Sr0.4MnO3)

Abstract

Nanocrystalline La0.6Sr0.4MnO3 sample with perovskite structure was successfully prepared by mechanochemical synthesis. Mechanical treatment for 10 h followed by annealing at 1100 °C results in the formation of single perovskite lanthanum strontium manganite (LSMO) phase with rhombohedral crystal structure and R 3 ¯ C symmetry. The heat-treated sample crystallite size, calculated from X-ray diffraction pattern, was about 84 nm. The scanning electron microscope images indicated a high degree of fine structure. The formation of single perovskite phase was confirmed by FTIR measurements. The magnetic measurements showed the soft ferromagnetic behavior of the obtained sample. The saturation magnetization was found to be lower than that expected from theoretical calculation for perfect ferromagnetic ordering and lower than the saturation magnetization published for bulk sample. This was explained in the light of the core/shell model of manganite nanoparticles. The obtained sample was found to have a negative coefficient of magnetoresistance at room temperature of about (−3.5%) with the application of 25 kOe magnetic field.