  Polymer-piezoceramic 0-3 composites combine the flexibility of the polymers
and the excellent piezoelectric properties of the ferroelectric based ceramic.
While grain size of the ceramic powder is one of the important considerations
in the fabrication of such composites, a correlation relating poling field
induced structural changes and its possible influence on the overall
piezoelectric response of the composite is still lacking. In this paper, we
examine this issue on a 0-3 piezo-composite comprising of a ceramic powders of
a low-lead piezoelectric alloy (x)Bi(Ni1/2Zr1/2O3-(1-x)PbTiO3 in proximity of
its morphotropic phase boundary, and polyvinylidene fluoride (PVDF) as the
polymer component. Composites were fabricated by fixing the volume fraction of
the ceramic while varying the grain size. We found a non-monotonic variation in
the piezo-response as a function of grain size. Structural analysis before and
after poling of the piezo-composites revealed evidence of poling induced
cubic-like to tetragonal irreversible transformation, the extent of which is
dependent on the grain size.
