Electrostatic model of the LiТаO3 ferroelectric

Abstract

Possible combinations of the electronic polarizability tensor components for oxygen and tantalum ions have been established based on the analysis of the refraction coefficients of LiТаO₃ crystal in the far-IR region. The local electric field on structurally nonequivalent ions in the LiТаO₃ unit cell was calculated within the modified point-multipole model. A combination of the electronic polarizability tensor components for oxygen and tantalum ions and their effective charges is established, which provides a good correspondence of the calculation results with the experimental data on LiТаO₃ crystals obtained by ⁷Li nuclear magnetic resonance and ¹⁸¹Та nuclear quadrupole resonance and with the known value of the crystal spontaneous polarization.