Effects of MnO addition on structure and electrical properties of lead-free antiferroelectric 0.96NaNbO₃–0.04CaZrO₃ ceramics

Abstract

Antiferroelectric 0.96NaNbO₃–0.04CaZrO₃ ceramics were fabricated by a solid-state reaction, and the effects of additive compounds of MnO were evaluated. We investigated the crystal structure, microstructure, dielectric, and electromechanical properties of 0.96NaNbO₃–0.04CaZrO₃ ceramics sintered at 1250–1400 °C. The sinterabilities of the undoped 0.96NaNbO₃–0.04CaZrO₃ ceramics were poor. The addition of MnO resulted in improved sinterability, but the addition of 3–5% sintering at 1350 °C caused partial melting of the sample, resulting in a slight decrease in density. X-ray diffraction revealed the superlattice reflections characteristic of antiferroelectrics in some of the sintered samples; however, the reflections were weak or disappeared with the addition of 3–5%, sintering at 1350 °C. When 3% MnO was added, 0.96NaNbO₃–0.04CaZrO₃ sintered at 1250 °C drew the constricted P-E hysteresis loops and s-E loops with rapid expansion due to switching at room temperature. These facts indicate that the antiferroelectric properties of 0.96NaNbO₃–0.04CaZrO₃ ceramics were stabilized by the addition of MnO.

Keywords:

• Antiferroelectrics
• NaNbO₃
• superlattice reflection
• sinterability
• double hysteresis loop