High Curie Temperature BiFeO3-BaTiO3 Lead-free Piezoelectric Ceramics: Ga3+ Doping and Enhanced Insulation Properties

Abstract

BiFeO3-BaTiO3 (BF-BT) is a promising high temperature lead-free piezoceramics due to their excellent piezoelectric properties with high Curie temperature (TC>500 °C). While the high leakage current density severely restricted its application. In this work, the leakage mechanism relative to the dielectric properties and piezoelectric properties were systematically studied with a special emphasis on gallium (Ga3+) adding effect in 0.7BiFe(1-x)GaxO3-0.3BaTiO3 (BFGax-BT, 0≤x≤0.10) ceramics. A high resistivity (ρ) of 2.73×1012 Ω·cm-1 and low leakage current (J) of 7.78×10-9 A·cm-2 were achieved at x=0.06, which attributes to the low oxygen vacancies (B). The J-E curves reveal different type of conduction process in BFGax-BT ceramics, including Ohmic conduction, space-charge-limited conduction (SCLC) mechanism and interface-limited Schottky emission. The BFGa0.06-BT ceramic exhibits excellent piezoelectric performance: d33=174 pC·N-1, TC=497 °C, kp=29 %.