Dielectric, piezoelectric, and pyroelectric studies of LiTaO3-derived ceramics sintered at 900°C following the addition of (LiF + MgF2)

Abstract

High-densified LiTaO3-type ceramics have been obtained by sintering at 900°C after the addition of small amounts of a LiF + MgF2 mixture. Partial hydrolysis of MgF2 and volatilization of either LiF, LiOH, or Li2O due to hydrolysis and partial substitution of F-ions by (OH−) occur during heat treatment. The ferroelectric Curie temperature Tc increases with the amount of additive. The ceramics have been polarized by heating to Tc and cooling down under a dc field. The piezoelectric and pyroelectric coefficients of such ceramics are approximately 30% and 20% of the corresponding values for a LiTaO3 single crystal.