Phase Transitions in Li, K and Ag Modified Na_1/2Bi_1/2TiO₃-SrTiO₃-PbTiO₃ Solid Solutions

Abstract

Influence of moderate substitution of Na by monovalent metals Li, K and Ag on structure, phase transitions and dielectric properties of 0.4Na_1/2Bi_1/2TiO₃-0.4SrTiO₃-0.2PbTiO₃ is studied. Substitution by Li increases, while substitution by K and Ag decreases tetragonality of unit cell. Li increases, Ag decreases while K weakly influences phase transition temperature. The characteristic for the parent phase relaxor state with T_t approaching T_m in case of substitution by K and Li transfers into diffused phase transition without T_m dependence on frequency and extended region of thermal hysteresis.

Keywords:

• NBT
• relaxors
• solid solutions
• phase transitions
• modificators

Acknowledgements

This work has been supported by the European Social Fund within the project “Support for Doctoral Studies at University of Latvia” and L'ORÉAL Latvian „For Women In Science” fellowship with the support of the Latvian National Commission for UNESCO and the Latvian Academy of Sciences.