On the Structural and Dielectric properties of sol-gel synthesized Copper doped Lanthanum Sodium Manganite (LNCMO) nanoparticles

摘要

La_(0.7)Na_(0.3)CuxMn_(1.x)O nanoparticles (LNCMO for x=0, 0.05, 0.1) are prepared by a modified sol-gel auto combustion method. The structural analysis of samples fired at different temperatures are carried out using X-Ray Diffraction (XRD). From XRD patterns, it is observed that the structure of LNCMO nanopowders exhibited a perovskite rhombohedral structure for x=0 and 0.5 and orthorhombic for x=0.1. Temperature and frequency dependence of dielectric permittivity and ac conductivity of LNCMO samples are also investigated. The impact of copper substitution on the dielectric properties of LNCMO is elucidated. The increase in dielectric constant for LNCMO, for x=0 and x=0.05 with temperature and the decrease in LNCMO sample for x=0.1 are investigated as an effect of increase in copper doping. The variation in dielectric constant and ac conductivity with frequency and temperature of sample with x=0.1 indicated a phase transition associated with the sample near room temperature.