Ferromagnetic resonance spectra of linear magnetosome chains.

The ferromagnetic resonance (FMR) spectra of oriented and non-oriented assemblies of linear magnetosome chains are calculated by solving the stochastic Landau-Lifshitz equation. The dependence of the shape of the FMR spectrum of a dilute assembly of chains on the particle diameter, the number of particles in a chain, the distance between the centers of neighboring particles, the mutual orientation of the cubic axes of particle anisotropy, and the value of the magnetic damping constant is studied. It is shown that FMR spectra of non-oriented chain assemblies depend on the average particle diameter at a fixed thickness of the lipid magnetosome membrane, as well as on the value of the magnetic damping constant. At the same time, they are practically independent of the number N_p of particles in the chain under the condition N_p ≥ 10. The FMR spectra of non-oriented assemblies of magnetosome chains are compared with that of random clusters of interacting spherical magnetite nanoparticles. The shape of FMR spectra of both assemblies is shown to differ appreciably even at sufficiently large values of filling density of random clusters.