Related Experiment Video
Updated: May 15, 2026

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
S-band ferromagnetic resonance spectroscopy and the detection of magnetofossils
Andreas U Gehring1, Jessica Kind, Michalis Charilaou
1Institute of Geophysics, ETH Zurich, , 8092 Zurich, Switzerland. agehring@erdw.ethz.ch
Abstract:
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.
Related Concept Videos
NMR Spectrometers: Overview
Atomic Nuclei: Magnetic Resonance
Ferromagnetism
NMR Spectrometers: Resolution and Error Correction
Double Resonance Techniques: Overview
Spin decoupling is usually achieved by...
Applications Of NMR In Biology
The...

