Dielectric relaxation of the double perovskite oxide Ba₂PrRuO₆

Samples of Ba₂PrRuO₆ were prepared by the solid state reaction method and the structure was characterized by X-ray diffraction (XRD). Scanning electron microscopy (SEM) and dielectric measurements were performed in order to investigate the morphology and electric properties of the ceramics. X-ray diffraction data reveal that the Ba₂PrRuO₆ samples are of the cubic crystal structure with the space group Fm3̄m at room temperature. The dielectric properties were studied in the range of 20 Hz to 1 MHz in the temperature range from 10 K to 300 K. Strong dispersion in frequency and a rapid increase in ε' are observed when T > 150 K. The observed steps of the ε'(T) curves are correlated with the peaks of the tan δ(T) curves, with the peak temperature shifting to higher values as the frequency increases. Impedance spectroscopy studies indicate the presence of grain and grain boundary relaxations in the sample at high temperatures, while at low temperatures only grain relaxation can be observed. Both grain and grain boundary relaxation times follow the Arrhenius law with activation energies of 0.16 eV and 0.17 eV, respectively.