Slow magnetoresistance relaxation in Fe/SiO2-nanocomposites

Abstract We report about the first time observing the logarithmic relaxation of the giant magnetoresistance (GMR) in Fe/SiO2-nanocomposites at relatively high temperatures with features characteristic for the glass-like behaviour. The model has been developed which describes the glass-like character of granular ferromagnetics and explains the quasi-threshold character of the slow GMR relaxation in ferromagnetic nanocomposites with temperature or magnetic field variations.