Nmr Studies of Bulk and Interface Structure in Co Based Multilayers

Abstract

ABSTRACTOwing to the sensitivity of the hyperfine field to the topological and chemical environment of the probe nuclei, NMR spectra can be considered as histograms of the short range order ruling the structure of the material under investigation. Complementary to diffraction techniques this gives a local insight on the structure in the direct space. We review recent structural investigations of cobalt layers imbedded in Co/X multilayers and particularly of buried interfaces. Special attention has been given to the way intermixing takes place at the interfaces as its influence on the multilayer properties may be of considerable importance. Co/Cu multilayers, a case of weakly miscible elements, have been specially investigated owing to their GMR properties. But also cases of solid solution forming elements (Co/Ru or Co/Cr) or compound forming elements (Co/Fe) have been thoroughly studied. The latter case, which shows a stabilization of a bcc Co phase, will be discussed against the bulk alloy phase diagram.