Defect Mechanism and Improved Dielectric Properties of Bismuth Ferrite Ceramics

Recently, multiferroic Bismuth ferrite (BiFeO3) has drawn great attention due to its interesting ferromagnetic and ferroelectric properties. In this work, nonstoichiometric Bi1+xFeO3±δ ceramics were synthesized by a... [ view full abstract ]

Recently, multiferroic Bismuth ferrite (BiFeO₃) has drawn great attention due to its interesting ferromagnetic and ferroelectric properties. In this work, nonstoichiometric Bi_1+xFeO_3±δ ceramics were synthesized by a conventional solid-state reaction method to understand the defect chemistry of BFO ceramics. The crystal structure, dielectric and high temperature conduction properties were investigated. Addition of the excess Bi₂O₃ decrease the Bi volatility in BFO ceramics. Polarization versus electric field (P-E) hysteresis loops and dielectric properties enhanced with Bi₂O₃ addition. To better understand the defect effects on the multiferroic properties, the electrical conductivity was measured under various oxygen partial pressure (pO₂) at high temperature. Following that, a new lead-free ABO₃-modified BiFeO₃–BaTiO₃ system was synthesized by adding optimal amount of excess Bi₂O₃ and its crystal symmetry, ferroelectric properties, and temperature stable dielectric properties were investigated.