The influence of boundary scattering on transport phenomena in ferromagnetic metal-dielectric nanocomposites

It is the rather common for metal-dielectric composites to have metallic grains with size about 10-100 Angstrom. This dimension is of the order of the bulk mean-free path of conduction electrons. Then the electron scattering at the boundaries between the adjacent grains (intergranular contacts) and at the interfaces between metallic grains and dielectric matrix would give a significant contribution to the total scattering and thus to the transport phenomena. We consider a simple model for intergranular contact and interface scattering and calculate the extraordinary Hall effect (EHE) in ferromagnetic nanocomposites taking into account the boundary scattering. The results of these calculations are in a qualitative agreement with the recent experimental data on giant EHE in nanocomposites (NiFe)(x)(SiO2)(1-x).