Conductive property of BiFeO3–BaTiO3 ferroelectric ceramics with high Curie temperature

Abstract

Abstract The (1-x)Bi1.05FeO3-xBaTiO3 (x = 0.30, 0.31, 0.32, 0.33) (abbrev. (1−x)BF-xBT) ceramics are successfully prepared via conventional solid-state sintering method. The XRD patterns indicate that the (1-x)BF-xBT ceramics possess pure perovskite structures. In addition, the oval P-E hysteresis loops demonstrate high conductive and dielectric losses in (1-x)BF-xBT ceramics. Ferroelectric properties (Pr = 18.6 μC/cm2) and high Curie temperature (Tc = 472 °C) are obtained in the ceramics. The conductive mechanism is comprehensively investigated by using impedance spectroscopy and XPS. The change in valence state is also characterized by XPS at room temperature, and the partial reduction in Fe3+ to Fe 2+ and Ti4+ to Ti3+ ions decreased the resistivity and the oval and unsaturated P-E hysteresis loop because of the weakly bound electrons. Results of the impedance spectroscopy and XPS indicate that the bulk is primarily responsible for the electric properties, and the charge carrier is mainly doubly ionized oxygen vacancies at the elevated temperature because of the activation energy Ea = 0.69 eV. This work provides an instructive method for the fabrication of high-temperature insulation components.