Relaxor behavior and impedance spectroscopic studies of chemically synthesized SrCu3Ti4O12 ceramic

Abstract SrCu3Ti4O12 (a double perovskite) has been synthesized by a chemical technique. The scanning electron micrograph of the pellet sample, recorded at room temperature, exhibits uniformly distributed rod and sheet like grains over the entire surface. Detailed dielectric studies of the sample exhibit relaxor-like behavior with high dielectric constant (104 at 1 kHz and 233 °C). Up to 100 °C, only bulk (grain) effect contributes to the polarization mechanism, and the corresponding Cole-Cole plot depicts a single depressed semicircular arc tilted at an angle of 39.97° to the real axis with a relaxation distribution parameter of 0.556. The real and imaginary parts of the dielectric constant, computed on the basis of the modified Debye equation, tally with the experimental results. The AC conductivity data analyzed using Jonscher’s universal power law suggest that the correlated barrier hopping is the dominant conduction mechanism in the sample. Schottky type thermionic emission for the conduction mechanism across the grain boundary is confirmed from the J-E characteristics. The sample exhibits magneto-electric coefficient of 0.827 mV/cm Oe.