Fitting to magnetoresistance under weak localization in three dimensions

We discuss a number of suggested explanations for observed discrepancies between theories of the quantum corrections to conduction, and recent magnetoresistance experiments on bulk metallic glasses. We emphasize the importance of competing effects, particularly the influence of magnetic impurities. Data showing these effects are presented and analyzed using a theory of Béal-Monod and Weiner to account for the direct magnetoresistance from the spin scattering and the magnetic field dependence of the spin-flip dephasing rate. Throughout, we provide useful numerical procedures for the efficient evaluation of the theoretical expressions used in analyzing such data, and point out that some theoretical expressions must be altered when considering strongly enhanced paramagnetic systems.