Document Type
Article
Publication Date
2007
Journal or Book Title
Physical Review B - Condensed Matter and Materials Physics
Volume
76
Issue
5
First Page
054406-1
Last Page
054406-10
DOI
10.1103/PhysRevB.76.054406
Abstract
The magnetic properties of biologically produced magnetite nanocrystals biomineralized by four different magnetotactic bacteria were compared to those of synthetic magnetite nanocrystals and large, high-quality single crystals. The magnetic feature at the Verwey temperature TV was clearly seen in all nanocrystals, although its sharpness depended on the shape of individual nanoparticles and whether or not the particles were arranged in magnetosome chains. The transition was broader in the individual superparamagnetic nanoparticles for which TB < TV, where TB is the superparamagnetic blocking temperature. For nanocrystals organized in chains, the effective blocking temperature TB > TV and the Verwey transition is sharply defined. No correlation between particle size and TV was found. Furthermore, measurements of M (H,T,time) suggest that magnetosome chains behave as long magnetic dipoles where the local magnetic field is directed along the chain. This result confirms that time-logarithmic magnetic relaxation is due to the collective (dipolar) nature of the barrier for magnetic moment reorientation.
Copyright Owner
The American Physical Society
Copyright Date
2007
Language
en
File Format
application/pdf
Recommended Citation
Prozorov, Ruslan; Prozorov, Tanya; Mallapragada, Surya K.; Narasimhan, Balaji; Williams, Timothy J.; and Bazylinski, Dennis A., "Magnetic irreversibility and the Verwey transition in nanocrystalline bacterial magnetite" (2007). Chemical and Biological Engineering Publications. 160.
https://lib.dr.iastate.edu/cbe_pubs/160
Included in
Atomic, Molecular and Optical Physics Commons, Biochemical and Biomolecular Engineering Commons
Comments
This article is from Physical Review B 76 (2007): 054406, doi: 10.1103/PhysRevB.76.054406.