The superparamagnetic gamma-Fe2O3 nanoparticles (average diameter of 2.5 nm) encapsulated in polypropylene imine) dendrimer have been investigated by Electron Magnetic Resonance (EMR). EMR measurements have been recorded in perpendicular and parallel configurations in the wide temperature range (4.2-300 K). It has been shown that the model based on the spin value S = 30, corresponding to the total magnetic moment of the nanoparticle, can be used to interpret the experimental results and the proof of the quantum behavior of gamma-Fe2O3 nanoparticles.
