Switching processes and the electronic subsystem in ferroelectric ceramic of the barium-lead niobate type

This paper is devoted to the study of the relation between switching processes and the states of the electronic subsystem in a ferroelectric ceramic. Experimental observations of the dielectric hysteresis loops at 5·10^–3 Hz, thermally stimulated currents, the relaxation of the conductivity, and the temperature dependence of the stationary conductivity in the temperature range 280–423 K were performed. Formulas are proposed for calculating the hysteresis loop and the coefficient of dielectric viscosity from the parameters of the hysteresis loop. It is established that for a ferroelectric ceramic of the BLN type charge carriers localized at the levels 0.18, 0.25, 0.27, and 0.37 eV play the determining role in the formation of the equilibrium ferroelectric state far from the phase-transition point. It is shown that the coefficient of dielectric viscosity for polycrystalline samples is determined by the relaxation time of the electronic subsystem and the orientation of the internal field in the sample.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 9–14, February, 1989.In conclusion we thank V. P. Kamentsev and A. V. Nekrasov for a useful discussion of this work.