Inelastic electron scattering mechanisms in clean aluminum films

Magnetoresistance data for clean aluminum films ($R_{\square }=0.2-4\mathrm{} \Omega$) are analyzed in terms of localization and superconducting fluctuations. The inferred inelastic-scattering rate ${\tau }_i^{-1\mathrm{}}$ is interpreted as the sum of electron-phonon and dirty-limit electron-electron processes. Extrapolation of these results for ${\tau }_i^{-1\mathrm{}}$ shows good agreement with results of superconducting nonequilibrium studies of Chi and Clarke for $R_{\square }\gtrsim 1 \Omega$. For lower $R_{\square }$, another inelastic mechanism is evident, possibly clean-limit electron-electron scattering.