Zum magnetischen Nachweis der Supraleitung aufgedampfter Metallschichten

There is described an apparatus for the statement of superconductivity and ferromagnetism of a single evaporated film in the temperature range from 1.8° to 300° K. The observation of the magnetic moment of the film in a homogeneous alternating magnetic field is made possible by means of a special device of two sense coils. Tests with Pb and Sn foils result in the known transition temperatures of bulk material. A Sn film in a highly disordered state is produced by quenching condensation. The magnetic transition of such a film is found to be 0.8° K higher than the transition temperature of the annealed film. The result agrees with the resistance measurements by W.Buckel and R.Hilsch. The magnetic measurement proves the increased transition temperature for the whole material of the film.