Tuning the temperature coefficient of resonant frequency for 8-layer twinned hexagonal perovskite Ba8ZnTa6O24 ceramics

• Published in: Journal of materials science. Materials in electronics 2016-10, Vol.27 (10), p.10078-10081
• Main Authors: Zeng, Sen, Ni, Guoqi, Kuang, Xiaojun
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Materials Science; Optical and Electronic Materials
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-016-5081-5

High-Q dielectric materials ilmenite MgTiO 3 , columbite MgNb 2 O 6 and cubic perovskite Ba 3 NiTa 2 O 9 with negative temperature coefficient of resonant frequency (τ f ) were selected as candidates for compensating the τ f of hexagonal perovskite Ba 8 ZnTa 6 O 24 . X-ray diffraction data shows that Ba 8 ZnTa 6 O 24 coexists with Ba 3 NiTa 2 O 9 but is not compatible with MgTiO 3 and MgNb 2 O 6 at high temperature. The τ f for the mixed hexagonal/cubic perovskite Ba 8 ZnTa 6 O 24 –Ba 3 NiTa 2 O 9 system is tunable via the temperature compensation effect and its quality factor may be improved via annealing the ceramics at high temperature to enhance the cation ordering in the cubic component. Permittivity ε r  ~ 22–25, Q× f  > 30,000 GHz and tunable τ f within ±10 ppm/°C were achieved in the range of about 50–80 wt% Ba 3 NiTa 2 O 9 for the hexagonal/cubic perovskite composite Ba 8 ZnTa 6 O 24 –Ba 3 NiTa 2 O 9 ceramics, which is suitable for the application as dielectric resonators and filters.