Effect of Cobalt Doping on Structural and Dielectric Properties of Nanocrystalline LaCrO3

Pure and Co doped Lanthanum chromite (LaCrO3) nanoparticles, LaCr1-xCoxO3 (0 <= x <= 0.3), have been synthesized through sol-gel process and their structural, morphological and dielectric properties have been studied. X ray diffraction patterns reveal that the samples are in single phase having orthorhombic structure with Pnma space group. Structural parameters are refined by Rietveld refinement using Fullprof software. Lattice parameters and unit cell volume are found to decrease with increase in Co doping. Crystallite size is calculated using Scherrer equation and is also found to decrease with increase in Co concentration. Surface morphology is examined using SEM-EDX analysis, which confirms the formation of regular and homogeneous samples without any impurities. The value of dielectric constant (epsilon') decreases with the increase in frequency while it enhances with the increase in Co concentration. The log (epsilon'xf) versus log (f) graphs have been plotted to verify the universal dielectric response (UDR) model. All the samples follow UDR model in the low frequency range.