Ferromagnetic resonance spectroscopic response of magnetite chains in a biological matrix

In this study ferromagnetic resonance (FMR) spectroscopy using different frequencies (4.02, 9.47, and 34.16 GHz) was applied to randomly distributed magnetotactic bacteria characterized by their alignment of equidimensional magnetite particles in a chain. Using this technique the coupling field between the aligned magnetite particles of 55 mT was determined. The non-linear frequency dependence of the spectral linewidth is interpreted by the strong influence of the anisotropy properties of the studied magnetic composite.