Re-entrant-like relaxor behaviour in the new 0.99BaTiO(3)-0.01AgNbO(3) solid solution.

A new solid solution of 0.99BaTiO(3)-0.01AgNbO(3) was prepared by a solid state reaction. Its structural, dielectric and ferroelectric properties were investigated. Besides the three phase transitions associated with pure BaTiO3, the dielectric permittivity shows an additional peak around 100 degrees C. This peak exhibits a dielectric relaxation satisfying the Vogel -Fulcher law, indicating typical relaxor behaviour. The relaxor state occurs after the paraelectric to ferroelectric phase transition upon cooling, i. e., inside the ferroelectric phase, indicating a re-entrant-like phenomenon. This unusual phase transition sequence has never been reported in canonical lead-based ferroelectrics. Moreover, the relaxor state arises from a tetragonal phase rather than from a cubic phase as observed in conventional complex perovskite relaxors.