Electronic structure and magnetization of Fe-Co alloys and multilayers

The magnetic properties and electronic structure of bcc Fe-Co alloys and mu ltilayers are investigated with the first-principles molecular cluster disc rete variational method. The density of states and the contact interactions are obtained for the central atom of each cluster. Besides the local magne tic moment and the isomer shift the occupancies of 3d, 4s, and 4p shells ar e investigated when Co atoms are introduced in the immediate vicinity of ir on sites. The calculations indicate a varying magnetic moment for Fe atoms and a constant value for Co atoms which is in agreement with experiments. F or the superstructures, our results indicate a strong dependence of the loc al moment, contact field, and isomer shift for Fe atoms with the thick of i ron layers. The internal field increases for thicker Fe layers while the lo cal moment decreases which is also in accordance with experimental predicti ons. (C) 1999 American Institute of Physics. [S0021-8979(99)01608-4].