Low-temperature electron paramagnetic resonance in silver-iron oxide nanoparticles

Water in oil microemulsion technique has been used to obtain silver nanoparticles with a mean size of 7 nm surrounded by a matrix of 2 nm γ-Fe2O3 nanoparticles. Magnetic measurements of the sample exhibit a cusp in the ZFC curve at 50 K, which corresponds to the blocking temperature. A detailed study of the thermal evolution of EPR spectra has been performed in the samples. It has been shown that the linewidth, the resonance field and the intensity of the EPR line show different behaviour near the blocking temperature.