Electrical properties of Co-doped CaCu3Ti4O12

Co-doped CaCu3Ti4O12 samples were synthesized by solid-phase reaction. Electrical properties were studied by impedance spectroscopy in wide temperature (25-450 degrees C) and frequency (10 Hz-10 MHz) intervals. It was shown that the presence of the copper oxide interlayer significantly reduces the value of the dielectric constant. The amount of impurity copper in the CaCu(3)T(i)4-.Co.O-12-(delta) samples (x = 0.06; 0.12; 0.24) rise with an increase in the cobalt content. The samples are characterized by a granular microstructure, with an average grain size ranging from 2 to 10 mu m. The impedance of the samples was simulated at a temperature of 25 degrees C and in the range of 100-450 degrees C. It was found that the samples are characterized by low- and high-frequency polarization. The conductivity activation energy varied from 0.94 to 0.87 eV depending on the cobalt content. The CaCu3Ti3.94Co0.06O12- delta sample are characterized by the best values of the dielectric permittivity and the dielectric loss tangent, epsilon = 400 and tan delta = 0.2 (at 1 MHz and room temperature), respectively.