Structural, dielectric and field-induced strain properties of la-modified Bi_1/2Na_1/2TiO₃-BaTiO₃-SrZrO₃ ceramics

Bi_0.5Na_0.5TiO₃ (BNT) based ceramics are considered potential lead-free alternatives for Pb(Zr,Ti)O₃(PZT) based ceramics in various applications such as sensors, actuators and transducers. However, BNT-based ceramics have lower electromechanical performance as compared with PZT based ceramics. Therefore, in this work, lead-free bulk 0.99[(Bi_0.5Na_0.5)_0.935Ba_0.065]_(1-x)La_xTiO₃-0.01SrZO₃ (BNBTLax-SZ, with x = 0, 0.01, 0.02) ceramics were synthesized by a conventional solid state reaction The crystal structure, dielectric response, degree of diffuseness and electric-field-induced strain properties were investigated as a function of different La concentrations. All samples were crystallized into a single phase perovskite structure. The temperature dependent dielectric response of La-modified BNBT-SZ ceramics showed lower dielectric response and improved field-induced strain response. The field induced strain increased from 0.17% for pure BNBT-SZ to 0.38 % for 1 mol.% La-modified BNBT-SZ ceramics at an applied electric field of 6 kV/mm. These results show that Lamodified BNBT-SZ ceramic system is expected to be a new candidate material for lead-free electronic devices.