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arXiv · 1904.10732

Probing the stability and magnetic properties of magnetosome chains in freeze-dried magnetotactic bacteria

Philipp Bender·Lourdes Marcano·Iñaki Orue·Diego Alba Venero·Dirk Honecker·Luis Fernández Barquín·Alicia Muela·M Luisa Fdez-Gubieda
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Abstract

\textit{Magnetospirillum gryphiswaldense} biosynthesize high quality magnetite nanoparticles, called magnetosomes, and arrange them into a chain that behaves like a magnetic compass. Here we perform magnetometry and polarized small-angle neutron scattering (SANS) experiments on a powder of freeze-dried and immobilized \textit{M. gryphiswaldense}. We confirm that the individual nanoparticles are single-domain particles and that an alignment of the particle moments in field direction occurs exclusively by a N\'eel-like rotation. Our magnetometry results of the bacteria powder indicate an absence of dipolar interactions between the particle chains and a dominant uniaxial magnetic anisotropy. Finally, we can verify by SANS that the chain structure within the immobilized, freeze-dried bacteria is preserved also after application of large magnetic fields of up to 1\,T.

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Philipp Bender, Lourdes Marcano, Iñaki Orue, Diego Alba Venero, Dirk Honecker, Luis Fernández Barquín, Alicia Muela, M Luisa Fdez-Gubieda. 2019-04-24. Probing the stability and magnetic properties of magnetosome chains in freeze-dried magnetotactic bacteria. https://doi.org/10.1039/c9na00434c

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