Effects of Ga content on the structure and electrical performances of 0.69BiFe1-xGaxO3-0.31BaTiO3 lead-free ceramics

Abstract Lead-free 0.69BiFe1-xGaxO3-0.31BaTiO3 (x, 0–0.06) piezoceramics were synthesized via traditional sintering techniques. The phase structure, dielectric, piezoelectric and ferroelectric performances of the ceramics were studied systematically. The results revealed that all the samples locate near MPB of rhombohedral (R)-pseudocubic (pC) phase coexistence, and that Ga doping has distinct influences on the R/pC phase content ratio. An appropriate content of Ga doping favors densification and grains growth of the ceramics during sintering. With the increment of Ga content, the Curie temperature of the samples shifts towards lower temperature owing to increased tolerance factor t of the perovskites, and enhanced diffuse phase transition behavior was observed. In addition, both the piezoelectric and ferroelectric property are sensitive to the concentration of Ga doping. Significantly, the excellent piezoelectric coefficient d33 up to 206 pC/N along with strong remanent polarization Pr of 25 μC/cm2 are obtained in 0.69BiFe0.985Ga0.015O3-0.31BaTiO3 materials which would be a promising substitute for the conventional lead zirconate titanate system ceramics.