Articles written in Bulletin of Materials Science
Volume 37 Issue 3 May 2014 pp 679-683
Microwave dielectric ceramics in Sr1-𝑥Ca𝑥La4Ti4.93Zr0.07O17 (0 ≤ 𝑥 ≤ 0.5) composition series were processed via a solid-state sintering rout. X-ray diffraction revealed single phase ceramics. Ca substitutions for Sr tuned 𝜏f towards zero with increased 𝑄u𝑓o values. In the present study, 𝜖r∼ 55, 𝑄u𝑓o ∼ 11960 GHz and 𝜏𝑓∼ 5.2 ppm/°C were achieved for the composition with 𝑥 = 0.3.
Volume 37 Issue 6 October 2014 pp 1215-1219
Microwave dielectric ceramics in the Sr1–𝑥Ba𝑥Ca4Nb4TiO17 (0 ≤ 𝑥 ≤ 0.75) composition series were fabricated via a solid-state mixed oxide route. All the compositions formed single phase in Sr1–𝑥Ba𝑥Ca4Nb4TiO17 (0 ≤ 𝑥 ≤ 0.75) solid solutions within the detection limit of in-house X-ray diffraction (XRD). The sintered microstructure of these ceramics comprised densely packed elongated and plate-like grains. The dielectric properties varied linearly with 𝑥. Relative permittivity (𝜀r) increased from 47.2 to 54.5, unloaded quality factor multiplying the resonant frequency (𝑄u 𝑓o) decreased from 11,984 to 9345 GHz and temperature coefficient of resonant frequency (𝜏f) increased from –78.6 to 20 ppm/°C with an increase in x from 0 to 0.75. In the present study, 𝜀r ≈ 51.6, 𝑄u 𝑓o ≈ 10,160 GHz (5.37 GHz) and 𝜏f ≈ –13.5 ppm/°C were achieved for Sr0.5Ba0.5Ca4Nb4TiO17 (𝑥 = 0.5) ceramics.
Volume 44, 2021
Continuous Article Publishing mode
Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020
Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
Physical Sciences 2020
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