Size dependence of structure and magnetic properties of La0.7Sr0.3MnO3 nanoparticles

Using a sol-gel method, Perovskite-type manganese oxides La0.7Sr0.3MnO3 nanoparticles with various grain sizes were prepared. A transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis were employed to identify the microstructure. A Rietveld refinement method was applied to determine crystallographic parameters. Results show that prepared-nanoparticles are single crystal, the edge length of the unit cell becomes longer and the angle between the edges becomes less deviated from 60° as the grain sizes decrease, and the crystal symmetry changes from rhombohedral to cubic as D ∼ 16 nm. The magnetic properties were investigated using a vibrating sample magnetometer, the magnetization is significantly lower than that of bulk sample.