Structure evolution and electrical properties of Y³⁺-doped Ba_1-xCa_xZr_0.07Ti_0.93O₃ ceramics

Lead free piezoelectric ceramics of Y³⁺-doped Ba _1-xCa_xZr_0.07Ti_0.93O₃ with x = 0.05, 0.10, and 0.15 were prepared. Composition and temperature-dependent structural phase evolution and electrical properties of as-prepared ceramics were studied systematically by X-ray diffraction, Raman spectroscopy, impedance analyzer, ferroelectric test system, and unipolar strain measurement. Composition with x = 0.10 performs a good piezoelectric constant d₃₃ of 363 pC/N, coercive field E_c of 257 V/mm, remanent polarization P_r of 14.5 μC/cm², and a Curie temperature T _m of 109°C. High-resolution X-ray diffraction was introduced to indicate presence of orthorhombic phase. Converse piezoelectric constant d ₃₃* of x = 0.10 composition performed better temperature stability in the range from 50°C to 110°C. That means decreasing orthorhombic-tetragonal phase transition temperature could be an effective way to enlarge its operating temperature range.