Spatially inhomogeneous ordering of B′ and B″ ions in ferroelectric ceramics pbb′0.5B″0.5O3

The analysis of the dielectric dispersion has shown that in PbSc 0.5 Ta 0.5 O 3 and PbSc 0.5 Nb 0.5 O 3 ceramics with uncompleted B' and B''-ions ordering the ferroelectric Curie points of the external and internal parts of the ceramic grain exist at different temperatures causing two anomalies in ε (T) curves. These results are explained within the scope of the model assuming the spatially inhomogeneous process of ordering in ceramics.