IMPEDANCE STUDY OF BICUVOX CERAMICS

Impedance spectra of BICUVOX (Bi2Cu0.1V0.9O5.35) with platinum or gold electrodes, measured over broad frequency and temPerature range, were simulated by the impedance of an equivalent circuit composed of resistors, capacitors and constant phase elements. The assignment of the circuit elements to the bulk of electrolyte and to the electrode process was proved by their scaling with the geometric factor and by comparison with the ac four-probe measurement. Separation of contributions of grain interiors and grain boundaries to the resistance of BICUVOX was possible below 670 K, The Arrhenius plot of the total conductivity consisted of two straight sections, with a change of slope at about 740 K. The charge transfer reaction at the electrode was evident above 770 K.