A generalized rule for large piezoelectric response in perovskite oxide ceramics and its application for design of lead-free compositions

We present a general rule for the perovskite oxide ceramics: "A large piezoelectric constant in ABO(3) perovskite ceramics can be obtained by tuning the weight ratio of A and B sites, WA/WB or WB/WA, to 3. Piezoelectric constant decreases significantly when WA/WB or WB/WA is in the range of 0.5-2.0, termed as forbidden zone." A comparative analysis was conducted for broad range of materials demonstrating the applicability of proposed rule. Further based on this rule optimized compositions in BaTiO3 and alkali niobate based systems were developed. Polycrystalline ceramics in modified BaTiO3 system were found to exhibit longitudinal piezoelectric coefficient (d(33)) of 330 pC/N, while alkali niobate ceramics showed d(33) of 294 pC/N. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3142442]