Composition‐driven broad phase boundary for optimizing properties and stability in lead‐free barium titanate ceramics

A new piezoelectric system of (1− x − y )BaTiO 3 ‐ y CaZrO 3 ‐ x BaSnO 3 ( BT ‐ y CZ ‐ x BS ) was designed to achieve enhanced piezoelectric/strain properties and temperature stability. First, the relationships between composition, phase, and electrical properties are systematically investigated. The broad phase boundary with successive rhombohedral‐orthorhombic (R‐O) and orthorhombic‐tetragonal (O‐T) was obtained in 0.04 ≤ x ≤ 0.05 and 0.04 ≤ y ≤ 0.07 by tailoring the relationship of composition and phase structure, confirmed by X‐ray diffraction, temperature‐dependent dielectric constants, and Raman spectra. The optimized piezoelectric coefficient of d 33 = 560 pC/N, high strain of >0.20%, and large converse piezoelectric coefficient of d 33 * = 1170 pm/V were realized. Second, the optimized piezoelectricity both demonstrate a stable performance with fluctuation <8% for d 33 * and 20% for d 33 between 22 and 60°C since the broad phase boundary is exhibited in this temperature range. We believe that this work is a successful example to optimize piezoelectric properties and enhance the stability for piezoceramics.