Thermokräfte abschreckend kondensierter Metallschichten

Abstract

For the first time it is reported on the annealing behaviour of the thermopower of quenched condensed metal films, which are evaporated in vacuum at liquid helium temperatures. The measurements concern Pb- and Sn-films, Au- and Cu-films as well as Au-films with small amounts of Fe, and Bi-films between 2 and 300 °K. It is shown that in all quenched films the phonon drag part of thermopower S_g is completely suppressed. In Pb and Sn the part of thermopowerS _e caused by electron diffusion is not changed remarkably by quenching, whereas in Au- and Cu-films it is much greater than in bulk material up to 250 °K. Annealing at higher temperatures leads to an irreversible decrease ofS _e. The well known giant thermopower due to Fe-impurities in gold is very much reduced by quenching. The characteristic minima appear again after annealing of these films. Amorphous Bi-films have thermopowers which are comparable with those of Pb and Sn. After crystallisation the negative thermopower is much greater and increases with increasing temperature of annealing.