APPARATUS FOR THE MEASUREMENT OF THE INITIAL SUSCEPTIBILITY OF QUENCH-CONDENSED SPIN GLASS-FILMS

An apparatus for the measurement of the absolute value of the paramagnetic susceptibility is described. With this apparatus the susceptibility of quench-condensed films is measured in situ in the temperature range 2.5-300K. The applied AC magnetic field varies between 0.5 and 11.5 mT at frequencies of 11-5500 Hz. DC fields up to 11.5 mT can be applied parallel to the AC field. Magnetic moments of mu >or=1012 mu B are detected at 2.2 mT (AC) and 1100 Hz. This sensitivity allows the study of films about 1 mu m thick with various magnetic additions, e.g. Mn, Fe and Co in non-magnetic host metals. As an example the initial susceptibility chi of amorphous Au 75Si19Fe6 and of polycrystalline Au 92Fe8 is measured.