Isothermal depolarization current in metal-oxide varistor ceramics under various polarizing fields

Abstract

A method of analysis of experimental kinetic dependences of isothermal depolarization currents in metal-oxide varistor ceramics composed of ZnO – Bi 2 O 3– CoO – Sb 2 O 3– SnO 2– MnO – B 2 O 3 has been proposed and tested. The method is based on reconstruction of dependences with the use of the Kohlrausch–Williams–Watt function. Expansion of the distribution and reduction of the average time of dielectric relaxation of the depolarization were found as the magnitude of the polarizing electric field increased. These findings have been interpreted in the framework of the notion of participation in the recharge of localized states more distant from the Fermi level in the crystallites of zinc-oxide ceramics under increased polarizing fields.