Ferromagnetic resonance spectroscopic response of magnetite chains in a biological matrix

Mastrogiacomo, Giovanni; Fischer, H.; García-Rubio, Inés; Gehring, A. U.

doi:10.1016/j.jmmm.2009.10.035

Cited by 21 publications

(33 citation statements)

References 18 publications

(26 reference statements)

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“…Detailed multi-frequency FMR study on intact MTB by Mastrogiacomo et al [33] showed that the low-field B eff arises from magnetosome chains that are aligned parallel to B ex . In such array, these chains are saturated in contrast to those with orientations different from B ex .…”

Section: Experimental Set-upmentioning

confidence: 99%

“…The broad peak at 140 mT, the minimum at 203 mT and the shoulder at about 170 mT originate from the contribution of magnetocrystalline anisotropy fields and the anisotropy fields owing to chains perpendicular to B ex (figure 3). The relatively high intensity of the low-field compared with the high-field resonance obtained from the MTB sample is due to the remanence magnetization of the bulk sample [33]. If magnetite has been exposed to a saturation field B sat , which is less than 300 mT, the remanence magnetization is about 50 per cent of magnetization at B sat for SSD particles [40].…”

Section: Experimental Set-upmentioning

confidence: 99%

“…asymmetry of the absorption spectra) permit a direct way to detect the anisotropy of magnetosome chains [11,[27][28][29][30][31][32]. Mastrogiacomo et al [33] showed that FMR experiments of MTB using microwave frequency of 4 GHz, i.e. S-band, yield pronounced resonance patterns for uniaxial anisotropy of magnetite chains.…”

Section: Introductionmentioning

confidence: 99%

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S-band ferromagnetic resonance spectroscopy and the detection of magnetofossils

Gehring

Kind

Charilaou

et al. 2013

J. R. Soc. Interface.

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We report the use of S-band ferromagnetic resonance (FMR) spectroscopy to compare the anisotropic properties of magnetite particles in chains of cultured intact magnetotactic bacteria (MTB) between 300 and 15 K with those of sediment samples of Holocene age in order to infer the presence of magnetofossils and their preservation in a geological time frame. The spectrum of intact MTB at 300 K exhibits distinct uniaxial anisotropy because of the chain alignment of the cellular magnetite particles and their easy axes. This anisotropy becomes less pronounced upon cooling and below the Verwey transition (T V ) it is nearly vanished mainly owing to the change of direction of the easy axes. In a natural sample, magnetofossils were detected by uniaxial anisotropy traits similar to those obtained from cultured MTB above T V . Our comparative study emphasizes that indispensable information can be obtained from S-band FMR spectra, which offers even a better resolution than X-band FMR for discovering magnetofossils, and this in turn can contribute towards strengthening our relatively sparse database for deciphering the microbial ecology during the Earth's history.

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Section: Experimental Set-upmentioning

confidence: 99%

Section: Experimental Set-upmentioning

confidence: 99%

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S-band ferromagnetic resonance spectroscopy and the detection of magnetofossils

Gehring

Kind

Charilaou

et al. 2013

J. R. Soc. Interface.

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“…Ferromagnetic resonance spectroscopy (FMR) is a powerful tool for analyzing the anisotropy of magnetic materials, and it has been applied to the study of MTB (18)(19)(20)(21)(22). Thus far, quantitative FMR analyses have been reported for cultured species of the a-proteobacteria class, such as Magnetospirrilum gryphiswaldense MRS-1 (23,24).…”

Section: Introductionmentioning

confidence: 99%

Anisotropy of Bullet-Shaped Magnetite Nanoparticles in the Magnetotactic Bacteria Desulfovibrio magneticus sp. Strain RS-1

Chariaou

Rahn-Lee

Kind

et al. 2015

Biophysical Journal

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Magnetotactic bacteria (MTB) build magnetic nanoparticles in chain configuration to generate a permanent dipole in their cells as a tool to sense the Earth's magnetic field for navigation toward favorable habitats. The majority of known MTB align their nanoparticles along the magnetic easy axes so that the directions of the uniaxial symmetry and of the magnetocrystalline anisotropy coincide. Desulfovibrio magneticus sp. strain RS-1 forms bullet-shaped magnetite nanoparticles aligned along their (100) magnetocrystalline hard axis, a configuration energetically unfavorable for formation of strong dipoles. We used ferromagnetic resonance spectroscopy to quantitatively determine the magnetocrystalline and uniaxial anisotropy fields of the magnetic assemblies as indicators for a cellular dipole with stable direction in strain RS-1. Experimental and simulated ferromagnetic resonance spectral data indicate that the negative effect of the configuration is balanced by the bullet-shaped morphology of the nanoparticles, which generates a pronounced uniaxial anisotropy field in each magnetosome. The quantitative comparison with anisotropy fields of Magnetospirillum gryphiswaldense, a model MTB with equidimensional magnetite particles aligned along their (111) magnetic easy axes in well-organized chain assemblies, shows that the effectiveness of the dipole is similar to that in RS-1. From a physical perspective, this could be a reason for the persistency of bullet-shaped magnetosomes during the evolutionary development of magnetotaxis in MTB.

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“…In an ensemble with randomly oriented assemblies, these anisotropy features are readily detectable in ferromagnetic resonance (FMR) experiments, which produce characteristic spectra with two or three low-field peaks and one strong high-field peak. [15][16][17][18][19] Therefore, we have investigated the evolution of magnetic anisotropy in growing MTB assemblies by FMR spectroscopy at a frequency of 9.8 GHz at ambient conditions.…”

mentioning

confidence: 99%