Electric-field-temperature phase diagram and the properties of AgNbO₃-modified Bi_0.5Na_0.5TiO₃

ABSTRACT

For some high-performance materials, AgNbO₃ (AN) is a possible doping material used to improve BNT-based ceramics and realize the measurement of their electric-field-temperature (E-T) phase diagrams. The dielectric, ferroelectric and electric field-induced strain responses of (1-x)(Bi_0.5Na_0.5) TiO₃(BNT)-xAgNbO₃ (0 ≤ x ≤ 0.1) piezoelectric ceramics were systematically investigated in this research. A large strain of 0.225% (corresponding to a large d₃₃ signal of 320 pm/V) similar to that obtained in the other electric field-induced binary BNT-based ceramics was achieved with 0.05 mol AgNbO₃ at room temperature. In addition, the electric-field-temperature (E-T) phase diagram for (1-x)(Bi_0.5Na_0.5)TiO₃-xAgNbO₃ (x = 0.03) was established. The transitions between the ferroelectric, ergodic, and nonergodic relaxor states of the materials were found as a function of composition and temperature.

KEYWORDS:

• Bi_0.5Na_0.5TiO₃
• electric-field-temperature (E-T) phase diagram
• electric field-induced strain
• lead-free piezoelectric

Funding

This work was financially supported by the National Key Project for Basic Research of China (2012CB619406), the National Natural Science Foundation of China (No. 11274174), the 111 project (Grant no. B12021), and the Fundamental Research Funds for the Central Universities (No. NJ20160005).