Longitudinal Magnetoresistance of Thin Metallic Films with Partially Specular Boundary Scattering

The longitudinal magnetoresistance of a thin metal film has been calculated using Chambers's method. It is assumed that the electron Fermi surface as well as the bulk mean-free path are spherically symmetric. Contrary to previous work based on the assumption of wholly diffuse surface scattering, we consider that scattering of electrons at the boundaries is partially specular. Explicit magnetoresistance curves have been calculated by numerical integration. It is found that low-field magnetoresistance depends quite sensitively on the fraction of specularly reflected electrons at the boundaries (ε). The resistance may change an order of magnitude between ε=0 and ε=0.9 in contrast to the corresponding {~} 10% variations in surface impedance associated with the anomalous skin effect. It is proposed that direct comparison between experimental data and the computed curves will yield information on the nature of boundary scattering.