RUSSIAN JOURNAL OF EARTH SCIENCES VOL. 7, ES4003, doi:10.2205/2005ES000177, 2005
[34] Shcherbakov et al. [1997] calculated the contribution of the elastic energy of envelopes from two-layer lipid membranes, 6 nm thick, to the stability of the chain structure of single-domain magnetite particles in magnetotactic bacteria. This problem can be transformed to a chain of superparamagnetic particles, separated by a PVA matrix, and this artificial system can be ranked as an analog of the biofilm produced by a colony of Fe-bacteria at the surface of minerals, where the bacteria become static. This result is important also for a new view for the formation of chemical remanent magnetization in nature, controlled by solutions. For instance, the laboratory experiments with amorphous ferric hydroxide, placed in the environment consisting of underground water, the samples of which had been collected from the overlying Cubero Sandstone, and the bacteria obtained from subsurface core samples (250 m below the ground surface) from the Morrison Formation, showed the substantial microbe recovery of the Fe(III) ions to their Fe(II) form [Fredrikson et al., 1998]. The primary reduction products of amorphous iron hydroxide (30% to 84%), produced during the incubation of 3 to 25 days, were siderite grains, 1 m m to 3 m m in size, vivianite crystals, 5-10 m m long and 0.5-1 m m wide, and the aggregates of magnetite grains of a few nanometers. The substantial magnetic interaction among magnetite particles in the aggregates of this kind might have been caused or intensified by the organic material of the cells. As follows from the results of this study, this interaction might have contributed to the stable natural remanent magnetization in the ambient geomagnetic field without the growth of the particles necessary for the record of the magnetic field that existed during the time of their formation.
Citation: 2005), Specific magnetic structure forming in polymer nanocomposites containing magnetite nanoparticles, Russ. J. Earth Sci., 7, ES4003, doi:10.2205/2005ES000177.
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