Electrical Resistivity of Lead Zirconate Titanate Ceramics Containing Impurities

Abstract

Electrical resistivity and its temperature variation are measured for lead zirconate titanate ceramics containing various metal oxides as impurities. The impurities can be classified from their influence on the resistivity of ceramics into the following three groups. (1) Impurities which keep the resistivity nearly unchanged (e.g. Fe₂O₃). (2) Impurities which increase it enormously because of electron-hole compensation (e.g. Nb₂O₅). (3) Impurities which increase it at first (electron-hole compensation) and then decrease it (e.g. Cr₂O₃). The decrease of resistivity in group (3) seems to be caused by the generation of segregated impurity layers which enclose the grains in ceramics. This postulate is confirmed quantitatively by the measurements of resistivity of the ceramics in which impurities are injected by means of thermal diffusion.