Re-entrant-like relaxor behaviour in the new 0.99BaTiO3–0.01AgNbO3solid 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 BaTiO(3), the dielectric permittivity shows an additional peak around 100 °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.