  We have measured the electronic heat capacity of thin film nanowires of
copper and silver at temperatures 0.1 - 0.3 K; the films were deposited by
standard electron-beam evaporation. The specific heat of the Ag films of
sub-100 nm thickness agrees with the bulk value and the free-electron estimate,
whereas that of similar Cu films exceeds the corresponding reference values by
one order of magnitude. The origin of the anomalously high heat capacity of
copper films remains unknown for the moment. Based on the low heat capacity and
the possibility to devise a tunnel probe thermometer on it, the Ag films form a
promising absorber material, e.g., for micro-wave photon calorimetry.
