Magnetic Properties of Magnetite Formed by Biomineralization and Chemical Synthesis
M. Timko, A. Džarová, P. Kopčanský, V. Závišová, M. Koneracká, J. Kováč
Institute of Experimental Physics, SAS, Watsonova 47, 040 01 Košice, Slovakia
A. Šprincová
Laboratory of Radiation Biology, JINR, Dubna, Russia
M. Vaclavíková, L. Ivaničová
LInstitute of Geotechnics, SAS, Watsonova 45, 040 01 Košice, Slovakia
and I. Vávra
Institute of Electrical Engineering, SAS, D'ubravská9, 841 04 Bratislava, Slovakia
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Received: 9 07 2007;
In this work, the magnetic properties of biologically produced magnetite (magnetosomes) by biomineralization process were compared to those of chemically synthesized Fe3O4. The coercivity of 185 Oe in magnetosomes is connected with the fact that the mean diameter is larger than critical size for transition from superparamagnetic to ferromagnetic behavior. A sharp magnetic transition at 105 K (Verwey transition) is clearly present in magnetosomes while in opposite, this transition is missing in Fe3O4.
DOI: 10.12693/APhysPolA.113.573
PACS numbers: 75.75.+a, 47.65.Cb, 87.83.+a