Critical superparamagnetic/single-domain grain sizes in interacting magnetite particles: implications for magnetosome crystals
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- Adrian R. Muxworthy
- Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
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- Wyn Williams
- Grant Institute of Earth Science, University of Edinburgh, Kings Buildings, West Mains Road, Edinburgh EH9 3JW, UK
書誌事項
- 公開日
- 2008-12-16
- 権利情報
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- https://royalsociety.org/journals/ethics-policies/data-sharing-mining/
- DOI
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- 10.1098/rsif.2008.0462
- 公開者
- The Royal Society
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説明
<jats:p>Magnetotactic bacteria contain chains of magnetically interacting crystals (magnetosome crystals), which they use for navigation (magnetotaxis). To improve magnetotaxis efficiency, the magnetosome crystals (usually magnetite or greigite in composition) should be magnetically stable single-domain (SSD) particles. Smaller single-domain particles become magnetically unstable owing to thermal fluctuations and are termed superparamagnetic (SP). Previous calculations for the SSD/SP threshold size or blocking volume did not include the contribution of magnetic interactions. In this study, the blocking volume has been calculated as a function of grain elongation and separation for chains of identical magnetite grains. The inclusion of magnetic interactions was found to decrease the blocking volume, thereby increasing the range of SSD behaviour. Combining the results with previously published calculations for the SSD to multidomain threshold size in chains of magnetite reveals that interactions significantly increase the SSD range. We argue that chains of interacting magnetosome crystals found in magnetotactic bacteria have used this effect to improve magnetotaxis.</jats:p>
収録刊行物
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- Journal of The Royal Society Interface
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Journal of The Royal Society Interface 6 (41), 1207-1212, 2008-12-16
The Royal Society
