Electron paramagnetic resonance linewidth of superparamagnetic particles

Superparamagnetic particles have been investigated by electron magnetic resonance. We have shown that the temperature dependence of the linewidth (above the freezing temperature) is sensitive to the pattern of particle size distribution. The behavior of the linewidth as a function of temperature is explained if we assume an anisotropic Dzyaloshinskii–Moriya type of interaction where the relaxation process occurs by a longitudinal component.