Synthesis and Structure Analysis of La_(0.5)Sr_(0.5)TiO_3 Nanoparticles Prepared by Thermal Decomposition Method

摘要

La_(0.5)Sr_(0.5)TiO_3 (LSTO) nanoparticles were synthesized by thermal decomposition method using Cl_3La, Cl_2Sr·6H_2O and C_(16)H_(28)O_6Ti as starting materials. The obtained precursor in a powder form was calcined at 700, 900, 1100 and 1300℃ for 3, 6 and 9 h in air. The structures of all samples were analyzed by XRD and some of them were taken for SEM, TEM and VSM measurements. The results from SEM showed the parallelpipe like shape of the particles with sizes distributed between 80 and 180 nm and the sizes of these particles were increased with the increasing of calcination temperature and time. The XRD's results showed the perovskite structure with the lattice type of orthorhombic at the calcination temperature of 900, 1100 and 1300℃ for 3, 6 and 9 h. The TiO and others unknown phase were found at low calcination temperature and they were disappeared as the calcination temperature and time were increased. The results of TEM support the orthorhombic structure of LSTO nanoparticles with crystallite size less than 200 nm as revealed by SEM and XRD. The magnetic property of all samples was measured by VSM and revealed that those prepared at 700, 900, and 1100℃ exhibit diamagnetic behavior, whereas one at 1300 shows ferromagnetism at room temperature. In this work, it is found that the nano-LSTO of high crystalline phase and purity can be prepared by thermal decomposition method at calcination temperature of 900 to 1300℃ in air for 6-9 h.