Rayleigh analysis of domain dynamics across temperature induced polymorphic phase transitions in lead-free piezoceramics (1−x)(BaTi0.88Sn0.12)–x(Ba0.7Ca0.3)TiO3

We carried out a Rayleigh analysis of the dielectric permittivity of a lead-free piezoceramic system (1-x)(BaTi0.88Sn0.12)-x(Ba0.7Ca0.3)TiO3 across the composition and temperature induced polymorphic phase transformations to determine the trend in the reversible and irreversible domain wall motion across the composition and temperature induced structural changes. Experiments were carried out on three representative compositions x = 0.10, 0.2, and 0.25 exhibiting rhombohedral, orthorhombic, and tetragonal phases at room temperature. While confirming that the irreversible Rayleigh parameter is large in the orthorhombic phase, we discuss a correspondence between the reduction in the coercive field and the corresponding increase in the irreversible Rayleigh parameter. We also show how the proximity of the Curie point to the polymorphic phase boundary greatly undermines this correspondence.