Ti doping and low-temperature sintering of BiFeO₃ nanoparticles synthesized by the solvothermal method

In this study, nanoparticles of ferroelectric BiFeO₃ (BFO) doped with 0, 5, and 10 mol% Ti were synthesized by an ethanol-based solvothermal method, and their densification behavior was investigated. The nanoparticles were densified via a normal sintering process at a low temperature of about 600 °C, resulting in dense bulk ceramics of undoped and Ti-doped BFO with a relative density of over 90%. The weight loss due to bismuth evaporation during sintering was suppressed below 0.6% because of the low sintering temperature. The crystal structure analysis of the resulting ceramics confirmed the incorporation of Ti ions into the Fe³⁺ site of BFO. The results of dielectric and X-ray photoelectron spectroscopies showed that Ti doping effectively decreased the concentration of Fe⁴⁺ in the ceramics, leading to suppression of the extrinsic dielectric responses due to the Maxwell–Wagner effect and the hopping motion of the localized holes.