Temperature-insensitive dielectric and piezoelectric properties in (1-X)K0.5Na0.5Nb0.997Cu0.0075O3-xSrZrO3 ceramics

Systematic investigation on phase transition, dielectric and piezoelectric properties of (1-x)K0.5Na0.5Nb0.997Cu0.0075O3-xSrZrO(3) (x=0, 0.03, 0.06, 0.09, 0.12, 0.15, abbreviated as KNNC-100xSZ) ceramics was carried out. Due to the coexistence of orthorhombic and tetragonal phase in a wide temperature range, a diffused polymorphic phase transition (PPT) region was achieved in KNNC with x >= 0.06. KNNC-12SZ ceramics exhibited high dielectric permittivity (similar to 1679), low dielectric loss (similar to 0.02) and small variation (Delta e'/epsilon'(25 degrees C)<= 15%) in dielectric permittivity from -78 degrees C to 237.3 degrees C. KNNC-6SZ ceramic possessed a high level of unipolar strain (similar to 0.15%) and maintained a smaller variation of +/- 12% under the corresponding electric field of 60 kV cm(-1) at 10 Hz from 25 degrees C to 175 degrees C. d(33)*, which was calculated according to the unipolar strain at 60 kV cm(-1), was 230 pm V-1 and remained stable below 100 degrees C. Therefore, our work provided a new promising candidate for temperature-insensitive capacitors and piezoelectric actuators. (C) 2017 Elsevier Ltd. All rights reserved.