Structural evolution, electrical properties and electric-field-induced changes of (0.8−x)PbTiO3–xBiFeO3–0.2BaZrO3 system near the morphotropic phase boundary

The crystal structures, piezoelectric property, dielectric transition and electric-field-induced changes in the structures and dielectric constant of (0.8−x)PbTiO3–xBiFeO3–0.2BaZrO3 (0.3 ≤ x ≤ 0.4) ceramics near the morphotropic phase boundary have been studied. All the ceramics could be indexed on the base of a tetragonal symmetry. The increasing concentration of BiFeO3 induces a reduction in the c/a ratio, ranged from 1.022 for x = 0.3 to 1.007 for x = 0.4. Accordingly, the piezoelectric coefficient (d33) reaches a maximum value at x = 0.34 (d33, 138 pC/N). A relaxor-type dielectric anomaly could be found for all the ceramics. The temperature of the maximum dielectric constant (T m) at 1 MHz and the degree of the diffuseness for the dielectric anomaly (δ) increase with BiFeO3 concentration, from 544 and 96 K for x = 0.3 to 574 and 154 K for x = 0.4. After poling, the ceramic for x = 0.34 shows an increase in the c/a ratio and an obvious decrease in the dielectric constant.