Microwave Dielectric Properties of Gallium-Doped Hexagonal Barium Titanate Ceramics |
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Authors: | Antonio Feteira Kumaravinothan Sarma Neil McN. Alford Ian M. Reaney fn Derek C. Sinclair |
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Affiliation: | Department of Engineering Materials, University of Sheffield, Sheffield S1 3JD, United Kingdom;School of EEIE, South Bank University, London SE1 0AA, United Kingdom |
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Abstract: | High-permittivity and low-loss ceramics with composition BaTi0.92Ga0.08O2.96 have been prepared in the BaO–Ga2O3–TiO2 system using the mixed-oxide route. This compound forms as the hexagonal polymorph (6 H ) of BaTiO3 with the space group P 63/ mmc . The dielectric properties of dense ceramics have been studied, at microwave frequencies, with the ceramics fired at 1450°C under flowing oxygen gas; the results are a relative permittivity, ɛr, of ∼74 and a quality factor, Q · f r, of ∼7815 at 5.5 GHz. The quality factor is strongly influenced by the sintering conditions (temperature and atmosphere), whereas the relative permittivity is not influenced significantly by ceramic processing for pellets ≥93% of the theoretical X-ray density. To our knowledge, this is the first report of microwave dielectric resonance in a perovskite-type BaTiO3-based ceramic. |
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Keywords: | barium titanate gallium/gallium compounds dielectric materials/properties microwaves |
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