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

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 T_c increases with the amount of additive. The ceramics have been polarized by heating to T_c 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.