Electrical characterizations of PZT ceramics in large frequency and temperature ranges

Electrical properties of PbZr0.75Ti0.25O3 ceramics have been characterized. The measurements have been made in frequency ranging from 20 to 2.109 Hz and between 20 and 730 °C for low and medium frequencies. Typically at room temperature, the dielectric constant ɛ′ is higher than 500 at 1 MHz whereas the loss tangent is close to 0.01. From ɛ′(T) measurements, the Curie temperature of our sample has been determined at 320 °C. In the paraelectric state, ɛ′(T) follows the empirical Curie–Weiss law near the phase transition which is of second order type. The increase of ɛ′ observed at high temperatures and low frequencies in the paraelectric state are explained: this abnormal behavior is due to the migation of oxygen ions towards the electrodes, creating an additional non-ferroelectric interface which generates a Maxwell–Wagner effect.