IMPEDANCE SPECTROSCOPY ON YSZ WITH IRON-OXIDE AS ADDITIVE

Doping effect of iron-oxide to YSZ (9 mol% yttria) on its electrical properties has been studied by impedance spectroscopy technique. The separation of bulk resistance (Rb), grain boundary resistance (Rgb) and electrode resistance (Re) was made easier when the impedance data were plotted in the complex plane. A parallel circuit of Rgb and Cgb, which corresponds to the capacitance of the grain boundary, gives a semicircle as a first approximation. The shape of Rgb versus ion oxide content curve is similar to that of Egb (the activation energy of the grain boudary curve). On the other hand, shape of Cgb curve correlates to change of Eb, which is the activation energy for the bulk resistivity. These results can be explained in terms of an accumulation of carrier species in the grain boundary. © 1990.