Particles size distribution and temperature dependence of coercivity and remanence in sputtered Co/Cu granular films

The effects related to particle size distribution on the temperature dependence of coercive field and of the ratio between the remanent and saturation magnetization of granular Co/Cu films grown by sequential sputtering, have been studied with magneto-optic Kerr effect measurements in the temperature range 8.5-60 K. We worked out a generalized model that includes also temperature effects related to non-uniform single-domain particle size distribution. The model predictions account excellently for the observed temperature behavior of both coercive field and ratio between the remanent and saturation magnetization. We find that a symmetric particle size distribution (Gaussian) accounts better for the experimental results than an asymmetric one (log-normal).