Electromechanical Resonance Study of the Diffuse Ferroelectric Phase Transition in BaTi1−xSnxO3Ceramics

Analysing piezoelectric length vibrations of bar-shaped samples, we have investigated the elastic compliance sE 11 (T) in the vicinity of the ferroelectric phase transition of BaTi 1 −xSnxO 3 ceramics. We observe the peak of the elastic compliance sE 11 (T) at the temperature Tm (s) below the peak temperature Tm (ϵ) of the permittivity ϵ 33 T(T). In the range x ≤ 0.1, which includes compositions with diffuse ferroelectric phase transition, the difference Tm (ϵ)−Tm (s) is rather small, and results mainly from the overlap of the s 11 E(T) peak with the elastic anomaly at the tetragonal-orthorhombic phase transition temperature T 1 . The “true” decoupling of the dielectric and elastic anomaly seems to be restricted to the relaxor state of BaTi 1 −x SnxO 3 , indicating different temperature evolution of the energy barrier distribution for 180° switching and non-180° reorientation of polar clusters.