NMR and spin relaxation in systems with magnetic nanoparticles

The H-1 NMR spectra and spin dynamics of the host systems have been studied in liquid and solid suspensions of gamma-Fe2O3 nanoparticles. Significant broadening of H-1 NMR spectra and growing relaxation rates were observed with increased concentration of nanoparticles in the liquid systems, with the relation T-1/T-2 depending on the particular host. Solid systems demonstrate inhomogeneous broadening of the spectra and practically no dependence of T-1 upon the nanoparticle concentration. We explain the experimental results taking into account the predomination of self-diffusion as a source of the relaxation in liquid suspensions, and estimate effective parameters of relaxation in the systems under study.