Dielectric relaxation property and barrier layer formation in CrNbO4 oxides

CrNbO4 ceramics were produced under different sintering temperatures using a modified solid-state reaction method. A single-phase solid solution in the specimens was detected when sintered at temperatures below 1623 K. The results indicated that the crystals have tetragonal rutile-type structures. Dielectric constant and dielectric loss were measured as a function of frequency (80 Hz–1 MHz) and temperature (233–473 K). The activation energy for samples sintered at 1523 K, 1573 K and 1623 K were 0.102 eV, 0.108 eV and 0.094 eV, respectively. The values of the relaxation time constant τo are of the order of 10−10 s. A higher value of the dielectric constant is due to the formation of barrier layer between the grain boundaries. Orientational and space charge polarization contribute to the observed dielectric behavior.