Anomalous Grain Growth in Donor-Doped Barium Titanate with Excess Barium Oxide |
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| Authors: | Miha Drofenik Darko Makovec Igor Zajc Hans T Langhammer |
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| Affiliation: | Faculty of Chemistry and Chemical Engineering, University of Maribor, Maribor, Slovenia;Ceramics Department, Joz?ef Stefan Institute, 1111 Ljubljana, Slovenia;Department of Physics, Martin–Luther–Universität Halle–Wittenberg, Halle/Saale, Germany |
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| Abstract: | Grain growth and semiconductivity of donor-doped BaTiO3ceramics with an excess of BaO and additions of SiO2or B2O3were studied. The microstructures and electrical measurements on sintered samples revealed that their electrical properties are related to the microstructure development of the sintered samples. Samples heated with an excess of BaO developed a normal microstructure during sintering, as a consequence of normal grain growth (NGG), and were yellow and insulating. In contrast, samples with an excess of BaO and an addition of SiO2or B2O3exhibited anomalous grain growth (AGG) and were dark blue and semiconducting after sintering. When some BaTiO3seed grains were embedded in a sample of donor-doped BaTiO3with an excess of BaO (without SiO2or B2O3), AGG was observed, i.e., some seed grains grew into large grains and were blue and semiconducting. An explanation is given for why AGG is responsible for the oxygen release and the formation of semiconducting grains in donor-doped BaTiO3and not NGG. |
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| Keywords: | barium titanate barium oxide grain growth semiconductors |
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