Structural dependence of the elecro-optic properties of some plzt ceramics

Abstract

Measurements of the birefringence of a series of PLZT ceramics with 7.5% lanthanum and Zr/Ti ratio varying from 50/50 to 76/24 are reported. It is found that an expression of the form Δn = -1/2n3gP2 is generally followed, where P is the polarization and the g coefficients are determined by the structure; for rhombohedral symmetries g = 0.020 m4/C2, for orthorhombic symmetriess g = 0.017 m4/C2, for tetragonal symmetries g = 0.011 m4/C2. Under certain conditions of composition and field, g coefficients lie between those determined for the tetragonal and ortho-rhombic symmetries, suggesting the presence of a mixture of tetragonal and orthorhombic grains. The tetragonal-orthorhombic phase change has been followed utilizing the change in g coefficients.