Interrelationship of Micro- and Macro-Structure with Physical Properties of Binary Acentric Oxide Ferroelastic and Paraelastic Crystals

摘要

On the plane of oxide bond lengths the ellipses of acentricity have been displayed for noncentrosymmetric (NCS) oxide crystals distributed over 4 groups of polar and nonpolar paraelastics-ferroelastics. The dependence of nonlinear optical susceptibility chi~(2) on the shortest oxide bond length has been revealed. Three characteristic regions are found inside the ellipses showing three different chi~(2) levels: (1) crossing part of ellipses; (2) two symmetrical parts of ellipses outside crossing part. On this basis a method has been proposed for design of new acentric crystals promising a high chi~(2).