Influence of calcium on the ferroelectricity of modified lead titanate ceramics

Abstract Lead titanate ceramics modified with 24, 30, 35 and 40 mole% of calcium have been obtained. The thermal behaviour of permittivity as well as that of pyroelectric coefficient present a larger broadening the larger the Ca content, which could be adscribed to an increasing disorder on the Ca and Pb arrangement. On the other hand the diminishing of tetragonality with increasing Ca amount causes the decrease of coercive field, which favors the 90° domain reorientation; the moderate strains produced on poling could justify the minimum poling reversal effects on piezoelectricity.