Obtention and characterizationof modified Bi₂ Sr Nb₂ O₉ aurivillius-typeceramics

Abstract

Aurivillius ferroelectric ceramics, based on the Bi₂Sr Nb₂O₉ compound, have been developed by making isomorphic substitutions in the (Bi₂O₂)²⁺ layer. High density ceramics were obtained by the uniaxial hot-pressing sintering technique. The macroscopic characterization was carried out by measuring both the dielectric constant, in the frequency range from 100Hz to 15MHz at temperatures between 20°C and 850°C, and piezoelectric parameters. We found that increasing the amount of cation Bi³⁺ substitution results in higher transition temperature values. Samples showed a high electrical resistivity that made poling difficult. Anyway, we found an important piezoelectric activity in the samples with tellurium present in their composition, with d₃₃ greater than 11pC/N.