Enhanced electromechanical properties of (1-x)BiFeO₃–BaTiO₃–xLiNbO₃ ceramics by quenching process

A new lead-free piezoelectric ceramics (1–x) (0.67Bi_1.05FeO₃ – 0.33BaTiO₃)–x LiNbO₃, abbreviated as BFBT-LNx (x = 0.00–0.030), were fabricated by conventional mixed oxide route following by quenching process and crystal structure and electromechanical properties were discussed. X-ray diffraction pattern showed that LiNbO₃ addition into 0.67Bi_1.05FeO₃ – 0.33BaTiO₃ system did not caused any significant change in crystal structure. However, an obvious variation in electrical properties was observed. It is revealed from electrical properties that the modification of LiNbO₃ induces a phase transition from a ferroelectric to relaxor state in the 0.67Bi_1.05FeO₃ – 0.33BaTiO₃ system. At optimum composition (x = 0.010), enhanced field-induced strain with large dynamic piezoelectric constant S_max/E_max = d^*₃₃ = 500 pm / V at a relatively low field of 3.5 kV / mm with lower hysteresis loss of 40% was recorded. For this composition, a high Curie temperature T_C ~ 390 °C was found. These properties suggests that the synthesized system is promising for high temperature actuator applications.