Hot-electron effect in palladium thin films

We have measured the hot-electron effect in sputtered palladium thin films at ultracryogenic temperatures. The temperature of the Joule-heated electron gas has been measured using a SQUID-based noise thermometer. Results are consistent with a T-3 dependence of the electron-phonon scattering rate, as reported for other materials. This dependence is in contrast with some theoretical predictions for the electron-phonon scattering rate in metals in the dirty limit and with recent experimental results on other metals.