Giant Hall effect of (Ni 90Co 10) x (SiO 2) 1-x nanogranular films at percolation threshold

The series of (Ni90Co10) (x) (SiO2)(1-) (x) nanogranular films were fabricated using the magnetron sputtering technique. The Hall effect of these films increased as the fraction of permalloy metal composition decreases near percolation. The maximum saturated Hall resistivity was found to be 4.32 mu cm in (Ni90Co10)(55)(SiO2)(45) film at room temperature, about two orders of magnitude larger than that of pure ferromagnetic metallic films. The atomic fraction at the quantum percolation threshold was accurately proved with the Rutherford backscattering (RBS) for the first time.