Enhanced piezoelectric and ferroelectric properties in the BaZrO_3 substituted BiFeO_3-PbTiO_3

摘要

BiFeO_3-PbTiO_3 (BF-PT) compounds possess very high Curie temperature and tetragonality compared to other PbTiO_3-based piezoceramics. The BaZrO_3 (BZ), with weakly ferroelectric active cations, was introduced into the BiFeO_3-PbTiO_3 to reduce the tetragonality (da) and improve the piezoelectric property. For the (0.8-x)BiFeO_3-0.2BaZrO_3-xPbTiO_3, the BaZrO_3 substitution can effectively decrease the tetragonality (c/a) from 1.18 to 1.02 for those compositions near the morphotropic phase boundary. The piezoelectric property of BiFeO_3-PbTiO_3 can be much enhanced with an optimal piezoelectric constant ～270 pC/N with a reduced Tc of 270 ℃. Both the temperature dependent dielectric properties and polarization loops verified the existence of antiferroelectric relaxor, which was not observed in previous reported BiFeO_3-PbTiO_3 based materials.