  Composition dependent Rayleigh and structural analysis was carried out on the
lead-free piezoceramics (1-x)(BaTi0.88Sn0.12)-x(Ba0.7Ca0.3)TiO3 at room
temperature. The system exhibits tetragonal (P4mm) structure for x > 0.21,
rhombohedral (R3m) for x < 0.13 and orthorhombic (Amm2) for 0.13<x<0.21.
Rayleigh analysis suggests that the irreversible contribution to the dielectric
response is enhanced in the single phase orthorhombic compositions in the
vicinity of the R3m-Amm2 and Amm2-P4mm phase boundaries, and not in
compositions exhibiting phase coexistences (x = 0.12 and 0.22). We also found a
correspondence between the irreversible Rayleigh parameter and the coercive
field in this system.
