Surface and interface studies with ASPIC

Magnetic properties at surfaces and interfaces have been investigated perfo rming Perturbed Angular Correlation (PAC) measurements in the UHV chamber A SPIC (Apparatus for Surface Physics and Interfaces at CERN) using different PAC probes. The results are: (i) determination of magnetic hyperfine field s of Se on Fe, Co, Ni which are explained by a theoretical study on the mag netic hyperfine fields of 4sp-elements in adatom position on Ni and Fe; (ii ) static magnetic hyperfine fields in ultrathin Pd on Ni(0 0 1) which indic ate an induced magnetic order in Pd; (iii) the observation of induced fluct uating magnetic interactions in Pd when thick Pd is in contact with Ni. Mon olayer-resolved measurements of the magnetic hyperfine fields in magnetized Pd are in accordance with theoretical predictions of the layer dependence of the induced magnetic moments in Pd.