Abstract Ceramic capacitors are extremely expected to attain the high dielectric permittivity (e′) and low loss tangent (tanδ) stabilized in an ultra-wide operating temperature range. In this work, we improved… Click to show full abstract
Abstract Ceramic capacitors are extremely expected to attain the high dielectric permittivity (e′) and low loss tangent (tanδ) stabilized in an ultra-wide operating temperature range. In this work, we improved e′, tanδ and their temperature stability by tailoring the distortion of oxygen octahedron with a different chemical composition in the K0.5Na0.5NbO3-based materials, and the relationships among the composition, crystal structure and dielectric performances were systematically investigated. By designing a series of material systems of K0.5Na0.5NbO3-0.02BiMO3 {KNN-M, M: Al, Fe, (Ti0.5Mg0.5), (Ti0.5Zn0.5), (Nb1/3Zn2/3)}, the decreased distortion of oxygen octahedron and enhanced symmetry in crystal structure could be well established, and a high dielectric permittivity (e’ = 1130 ± 15%) with stability in 25 °C–500 °C range was achieved in the KNN-NbZn ceramics. Particularly, a low loss tangent (tanδ ≤ 3%) was maintained up to 360 °C in the ceramics. Therefore, a balanced development of e’, tanδ and their temperature stability was achieved in the KNN-NbZn materials and we consider this work will bring a clear understanding about the temperature-stable behaviors of dielectric properties in KNN-based ceramic capacitors.
               
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