The electric and dielectric properties of Bi3Zn2Sb3O14 ceramic were studied by impedance spectroscopy. The measurements were performed in the frequency range 5 to 13 MHz and at temperature ranges from 25 to 700 °C. The permittivity was calculated by the variation of the imaginary part of the impedance (-Im(Z)) as function of 1/omega, where omega represents the angular frequency (2pif). The parameter epsilon = f(T) exhibits values in the range from 40 to 48. The dielectric losses (tandelta) show slight dependence with the temperature up to 400 °C. A strong increasing of the tandeltaoccurs at temperatures higher than 400 °C. In a general way, a decrease of the parameter tandelta occurs with the increasing frequency.

Impedance spectroscopy technique was used to investigate the electric properties of Zn7Sb2O12, an electroceramic with inverse spinel type structure. The electric characterization of the Zn7Sb2O12 semiconducting ceramic was performed at temperature from 250 to 550 °C, in the frequency range from 5 Hz to 13 MHz. Zinc antimoniate phase was synthesized by the polymeric precursors method. The bulk resistance curve as a function of temperature exhibits a thermistor behavior with negative temperature coefficient. The bulk conductivity follows the Arrhenius law with two linear branches of different slopes positioned at around a region of transition, 450 °C > T > 350 °C. The activation energy values at low temperature (< 350 °C) and high temperature (> 450 °C) are equals to 0.78 and 0.61 eV, respectively. The existence of a phase transition limiting these regions is discussed.