AC complex impedance investigation for RuO2-glass composites

As a function of RuO₂ volume fraction and heat treatment conditions, the AC complex impedance spectra of RuO₂-glass composites were investigated in the frequency range of 1 kHz-13 MHz, and equivalent circuits were analyzed based on the spectra. Because the amount of Ru ion in PbO-B₂O₃ -SiO₂-Al₂O₃-ZnO system glass increases with increasing reaction temperature and time, the electronic properties of the matrix are changed due to the impurity ion. The samples reacted at low temperature and for short time periods exhibited vertical lines in complex impedance spectra plots, which indicates that the samples consisted of lone capacitor circuits. As the temperature and the time increased, the spectra consisted of semicircle arcs representing RC combination circuits. Because the glass gap distance between RuO₂ particles decreases with increasing RuO ₂ content, the samples with greater RuO₂ content showed the change from a vertical line to semicircle arcs at a lower reaction temperature