Microwave assisted synthesis, characterization and humidity dependent electrical conductivity studies of perovskite oxides, Sm 1− xSr xCrO 3 (0 ≤ x ≤ 0.1)

Abstract

The perovskite oxides, Sm 1− x Sr x CrO 3 (0≤ x≤0.1) were synthesized by a microwave assisted combustion route from the constituent metal nitrates and urea. The single-phase oxides were characterized by X-ray diffraction (XRD) and the lattice parameters were evaluated. The perovskite oxides were subjected to DC conductance measurements over the temperature range 100–300 °C in air atmosphere from which activation energies were determined. The current was found to increase linearly with the applied field and exponentially against temperature indicating the ohmic nature of the electrode contacts. The activation energy values for DC conductance were found to be in the range of 0.38–0.56 eV. DC resistance measurements as a function of relative humidity in the range of 5–98% RH were carried out on sintered discs at 25 °C under static conditions from which the sensitivity factor, S f ( R 5%/ R 98%) for SmCrO 3, Sm 0.95Sr 0.05CrO 3 and Sm 0.90Sr 0.10CrO 3 were calculated to be 2198, 2971, 4510, respectively. The response and recovery characteristics were studied for Sm 0.90Sr 0.10CrO 3, which exhibited good linearity and very narrow hysteresis loop.