Investigation of the dielectric and thermal properties of sintered Li1−x Ta1−3x Ti4xO3 solid solution ceramics

Abstract

A series of twelve Li_1−x Ta_1−3x Ti_4xO₃ solid solution ceramics was sintered following the low-temperature metal alkoxide routes. Measurements of dielectric constants, dielectric losses, and heat capacities as functions of temperature and frequency are presented. The Curie temperature (T_c) in comparison to LiTaO₃ was reduced from 620°C to about 358°C in the Li_0.91 Ta_0.73 Ti_0.36O₃ ceramics. The heat capacity data showed no dependence on the bulk density or grain size. Also the mechanical properties of the undoped crystals appear to stay undisturbed. On the other hand, an apparently abnormal dependence of the Curie temperature on density was found. Heat capacity and dielectric loss decreased while the dielectric constant increased with the addition of Ti⁺⁴ doping in the LiTaO₃ structure. Overall, a good detector performance might indeed be obtained from these ceramic materials if they can be poled reproducibly.