Nanosized rare earth cobaltite LaCoO3 synthesized by urea combustion method

The structural, magnetic, and electrical properties of nano- and bulk samples of LaCoO3, prepared by a urea combustion method, are investigated in this paper. The structures of phases, calcined at different temperatures, were refined in two different space groups rhombohedral R-3c and monoclinic I2/a, and a good agreement was obtained between the observed and calculated XRD patterns. Magnetic measurements reveal that the magnetic susceptibility increases with reduction in particle size. It is observed that there are two types of mechanisms which govern the conduction in different temperature ranges of these samples, and no single law of conduction fits the entire range of temperature. In high temperature range (200-300 K), Arrhenius law fits well, while in the low temperature region (100-200 K), the conduction is governed by Efros-Shklovskii's (ES) hopping.