Composition and grain size-driven ferroelectric-relaxor crossover in Ba(Zr,Ti)O3 ceramics

First Ba(Zrx Ti1-x )O3 (BZT) ceramics with various compositions prepared by solid state, with high density, ho- mogeneous microstructures and grain sizes in the range (0.7-4) ?m were studied. Besides the dielectric and ferroelectric investigations, First Order Reversal Curves method was employed to describe the changes of the switching properties induced by composition and grain size, related to the ferroelectric-relaxor crossover. The dielectric and ferroelectric data for ceramics with similar grain sizes demonstrated the expected ferroelectric- relaxor crossover induced by increasing x. For a given composition (x = 0.10), the relaxor character increases whit reduction of the grain size. The FORC distribution shows almost zero reversible contribution and well- separated sharp irreversible component for larger grains, while more diffuse distribution with a continuous extension from Ec =0 (reversible) to Ec ?0 (irreversible, switching) is typical for fi ner grains.