Dielectric, piezoelectric, and pyroelectric studies of LiTa0₃-derived ceramics sintered at 900 °C following the addition of (LiF + MgF₂)

High-densified LiTa0₃-type ceramics have been obtained by sintering at 900 °C after the addition of small amounts of a LiF + lMgF₂ mixture. Partial hydrolysis of MgF₂ and volatilization of either LiF, LiOH, or Li₂0 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 LiTa0₃ single crystal.