Distribution of trivalent rare-earth additives between A and B sites in the ABO(3) PZT system

Lead zirconate titanate ceramics having composition at the morphotropic pha se boundary have been modified with 2 mol % rare-earth oxides of Er, Gd, Eu , Nd and La. The samples have been prepared using the standard solid state reaction route. The ionic radius of the additives investigated vary from 0. 088 to 0.106 nm. A theoretical model has been used which allows the additiv e cation distribution between A and B sites to be established from its ioni c radius. It has been concluded that the additive goes increasingly to the A site with increasing ionic radius. The amounts of lead monoxide liberated during sintering due to incorporation of the additives have been studied. Using this PbO loss data the distribution of the additive between A and B s ites has been calculated. It has been observed that the experimental result s agree well with theoretical calculations.