Temperature‐Stable Relative Permittivity from −70°C to 500°C in (Ba0.8Ca0.2)TiO3–Bi(Mg0.5Ti0.5)O3–NaNbO3 Ceramics |
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| Authors: | Aurang Zeb Yang Bai Tim Button Steven J Milne |
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| Affiliation: | 1. Institute for Materials Research, University of Leeds, , Leeds, LS2 9JT United Kingdom;2. School of Metallurgy and Materials, University of Birmingham, , Birmingham, B15 2TT United Kingdom |
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| Abstract: | Temperature‐stable relaxor dielectrics have been developed in the solid solution system: 0.45Ba0.8Ca0.2TiO3–(0.55 ? x)Bi(Mg0.5Ti0.5)O3–xNaNbO3. Ceramics of composition x = 0 have a relative permittivity ?r = 950 ± 15% over a wide temperature range from +70°C to 600°C. Modification with NaNbO3 at x = 0.2 decreases the lower limiting temperature to ?70°C, but also decreases relative permittivity such that ?r ~ 600 ± 15% over the temperature range ?70°C to 500°C. For composition x = 0.3, the low‐temperature dispersion in loss tangent, tan δ, (at 1 kHz) shifts to lower temperature, giving tan δ values ≤0.02 across the temperature range ?60°C to 300°C in combination with ?r ~ 550 ± 15%. Values of dc resistivity for all samples are of the order of 1010 Ω m at 250°C and 107 Ω m at 400°C. |
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