Weak localization and electron-electron interaction in percolating nickel films

We have investigated the scaling effects on the electron interface in inhomogeneous Ni films near the percolation threshold. As a result of the high exchange interaction of the conduction electrons, the conductance-anomaly at low temperature is due to the enhancement of the Coulomb e- e interactions by disorder. However, the magnetoresistance analysis shows that a small contribution of weak electron localization remains, while the enhancement of the e- e interactions is insensitive to the applied magnetic field. The signature of the modified dimensionality introduced by the percolating structure appears at very low temperature ( T < 4 K) when the phase coherence scale is of the same order as the percolation length. In this regime, the study of the magnetoresistance renormalization proves that localization and magnetism coexist in itinerant ferromagnetic materials.