NEW-TYPE OF OSCILLATORY EXCHANGE COUPLING INDUCED BY ORDERING IN THE MAGNETIC LAYERS

We found that formation of an ordered phase in alloyed magnetic layers induces new periods of exchange coupling oscillations in metallic mul tilayer systems. We studied on an ab initio level the case of c(2 X 2) ordering of random Co50Fe50(001) magnetic slabs embedded in fcc Cu. T he origin of the new periods can be correlated to critical points of t he spacer Fermi surface folded down to the Brillouin zone correspondin g to the c(2 X 2) superlattice.