Extraordinary Hall effect and giant magnetoresistance in the granular Co-Ag system

Abstract

We have studied the magnetotransport properties of a new metallic granular Co-Ag system. The spin-dependent electron scattering is revealed in the forms of a giant magnetoresistance and an extraordinary Hall effect, both of which are found to be strongly dependent on the Co particle size and the electron mean free path. The experimental correlation ${\mathrm{\ensuremath{\rho}}}_{\mathit{x}\mathit{y}}$\ensuremath{\propto}${\mathrm{\ensuremath{\rho}}}_{\mathit{x}\mathit{x}}^{3.7}$ uncovered is unexpected from existing theories. Interfacial scatterings of intermediate range are required in order to account for the anomalous magnetotransport in this magnetic granular system.