  It is well known that disordered relaxor ferroelectrics exhibit local polar
correlations. The origin of localized fields that disrupt long range polar
order for different substitution types, however, is unclear. Currently, it is
known that substituents of the same valence as Ti4+ at the B-site of barium
titanate lattice produce random disruption of Ti-O-Ti chains that induces
relaxor behavior. On the other hand, investigating lattice disruption and
relaxor behavior resulting from substituents of different valence at the B-site
is more complex due to the simultaneous occurrence of charge imbalances and
displacements of the substituent cation. The existence of an effective charge
mediated mechanism for relaxor behavior appearing at low (< 10%) substituent
contents in heterovalent modified barium titanate ceramics is presented in this
work. These results will add credits to the current understanding of relaxor
behavior in chemically modified ferroelectric materials and also acknowledge
the critical role of defects (such as cation vacancies) in lattice disruption,
paving the way for chemistry-based materials design in the field of dielectric
and energy storage applications.
