STUDIES ON ELECTRICAL-PROPERTIES OF Cr_(2-x)Ti_xO_(3+delta) BY IMPEDANCE SPECTROSCOPY

摘要

The compounds with compositions Cr_(2-x)Ti_xO_(3+delta) (where x = 0, 0.1, 0.2 and 0.3) were prepared by gel-entrapment method and characterized by XRD and thermal techniques. The electrical properties, such a, dielectric constant and ionic conductivity of these compounds were studied in the frequency range 10 MHz to 1 Hz, in the temperature interval 400 to 800 K, using impedance spectroscopy. The study showed that the dielectric constant of the sample increases up to 10 mole percent of TiO_2 doping and decreases on further increase in dopant concentration, in the dielectric constant versus temperature plot a phase transition is noted in the temperature range 650-700 K in all the samples. From Arrhenius plot, the activation energy for different compositions was derived, below and above the transition temperature. The results of the electrical measurement are explained on the basis of defect formation and ordering.