Localization and Electron-Interaction Effects in the Magnetoresistance of Granular Aluminum

Measurements of the magnetoresistance are reported for a series of granular aluminum specimens on the metal side of the metal-insulator transition. A clear separation can be made between the effects of localization and those of electron-electron interactions. Sufficiently far on the metal side localization effects dominate. At high fields, interactions account for the observed dependences on resistivity and temperature, both of which are absent in the localization theory.