Theoretical study of temperature dependence of spontaneous polarization, optical properties and free and clamped linear electrooptic coefficients of BaTiO₃ in the tetragonal phase

Abstract

The microscopic mechanism of refractive indices, birefringence, spontaneous polarization and free and clamped electrooptic effects of BaTiO₃ is discussed by using a microscopic model taking account of a quantum method based upon the orbital approximation and the dipole-dipole interaction due to the local field acting on the constituent ions. It is found that the electronic polarizabilities play a major role in these calculations and that the birefringence δn and the free and clamped linear electrooptic coefficients are in good agreement with the experimental data.

Key Words:

• BaTiO₃
• dielectric constant
• piezoelectric effect
• electrooptic effects
• electronic polarizability
• dipole-dipole interaction
• spontaneous polarization
• refractive index
• birefringence
• tetragonal phase