High Q Microwave Dielectric Ceramics in (Ni1−x Znx)Nb2O6 System |
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| Authors: | Sandeep Butee Ajit Kulkarni Om Prakash Ramnath PRC Aiyar Sumesh George Mailadi Sebastian |
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| Affiliation: | Department of Metallurgical Engineering and Materials Science, IIT-Bombay, Powai, Mumbai 400076, India;
Department of Metallurgy and Materials Science, Government College of Engineering, Shivaji Nagar, Pune 411005, India;
Centre for Research in Nanotechnology and Science (CRNTS), IIT-Bombay, Powai, Mumbai 400076, India;
National Institute for Interdisciplinary Science &Technology, Thiruvananthapuram 695019, India |
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| Abstract: | (Ni1? x Zn x )Nb2O6, 0≤ x ≤1.0, ceramics with >97% density were prepared by a conventional solid-state reaction, followed by sintering at 1200°–1300°C (depending on the value of x ). The XRD patterns of the sintered samples (0≤ x ≤1.0) revealed single-phase formation with a columbite ( Pbcn ) structure. The unit cell volume slightly increased with increasing Zn content ( x ). All the compositions showed high electrical resistivity (ρdc=1.6±0.3 × 1011Ω·cm). The microwave (4–5 GHz) dielectric properties of (Ni1? x Zn x )Nb2O6 ceramics exhibited a significant dependence on the Zn content and to some extent on the morphology of the grains. As x was increased from 0 to 1, the average grain size monotonically increased from 7.6 to 21.2 μm and the microwave dielectric constant (?'r) increased from 23.6 to 26.1, while the quality factors ( Q u× f ) increased from 18 900 to 103 730 GHz and the temperature coefficient of resonant frequency (τf) increased from ?62 to ?73 ppm/°C. In the present work, we report the highest observed values of Q u× f =103 730 GHz, and ?'r=26.1 for the ZnNb2O6-sintered ceramics. |
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