Negative magnetoresistance phenomenon in diluted granular multilayers Co$_{80}$Fe$_{20}(t)$|Al$_2$O$_3$

Several complex theories explaining the phenomenon of negative magnetoresistance (NMR) are discussed, observed in insulating diluted granular multilayers Co$_{80}$Fe$_{20}(t)$|Al$_2$O$_3$. In fact, this investigation is re-analyzing the experimental measurements of Co$_{80}$Fe$_{20}$ with low nominal thickness $t$ = 0.7 mm of granular layers obtained by H.G. Silva et al. [18]. Two theories such as quantum interference model and localized magnetic moments model are confronted with experimental measurements in order to provide physical explanations to NMR phenomenon.