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 rutiletype 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 To 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. (c) 2005 Elsevier B.V. All rights reserved.