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Critical single domain grain sizes in chains of interacting greigite particles: implications for magnetosome crystals

Muxworthy, A., W. Williams, A. P. Roberts, M. Winklhofer, L. Chang, and M. Posfai (2013), Critical single domain grain sizes in chains of interacting greigite particles: implications for magnetosome crystals, Geochem. Geophys. Geosyst., 14, 5430-5441, doi:10.1002/2013GC004973, OPEN ACCESS.

Abstract
Magnetotactic bacteria contain chains of magnetically interacting crystals (magnetosomes), which aid navigation (magnetotaxis). To improve the efficiency of magnetotaxis, magnetosome crystals (which can consist of magnetite or greigite) should be magnetically stable single domain (SD) particles. Larger particles subdivide into non-uniform multi-domain (MD) magnetic structures that produce weaker magnetic signals, while small SD particles become magnetically unstable due to thermal fluctuations and exhibit superparamagnetic (SP) behavior. In this study, we determined the stable SD range as a function of grain elongation and inter-particle separation for chains of identical greigite grains using fundamental parameters recently determined for greigite. Interactions significantly increase the stable SD range. For example, for cube-shaped greigite grains the upper stable SD threshold size is increased from 107 nm for isolated grains to 204 nm for touching grains arranged in chains. The larger critical SD grain size for greigite means that, compared to magnetite magnetosomes, greigite magnetosomes can produce larger magnetic signals without the need for inter-grain interactions.
Further information
BibTeX
@article{id1922,
  author = {A. Muxworthy and W. Williams and A. P. Roberts and M. Winklhofer and L. Chang and M. Posfai},
  journal = {Geochem. Geophys. Geosyst.},
  month = {dec},
  note = {OPEN ACCESS},
  pages = {5430-5441},
  title = {{Critical single domain grain sizes in chains of interacting greigite particles: implications for magnetosome crystals}},
  volume = {14},
  year = {2013},
  url = {http://onlinelibrary.wiley.com/doi/10.1002/2013GC004973/abstract},
  doi = {10.1002/2013GC004973},
}
EndNote
%0 Journal Article
%A Muxworthy, A. 
%A Williams, W.
%A Roberts, A. P.
%A Winklhofer, M.
%A Chang, L.
%A Posfai, M.
%D 2013
%V 14
%J Geochem. Geophys. Geosyst.
%P 5430-5441
%Z OPEN ACCESS
%T Critical single domain grain sizes in chains of interacting greigite particles: implications for magnetosome crystals
%U http://onlinelibrary.wiley.com/doi/10.1002/2013GC004973/abstract
%8 dec
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Printed 17. Aug 2019 23:09