Hyperfine fields in complex metallic systems: Co clusters embedded in Cu

We have used first-principles linear muffin tin orbital (LMTO-ASA) electron ic structure calculations, implemented directly in real space (RS) to theor etically investigate the behavior of the hyperfine field of Co clusters emb edded in fee Cu. We find that the magnitude of the dominant contact contrib ution to the hyperfine field decreases significantly as one goes from the C o site at the center of the cluster to those at the Co-Cu interface. To bet ter understand this behavior, we use a simple model which closely reproduce s the first-principles calculations, but is physically more transparent. Ou r approach can partially deconvolute the several dependences, calling atten tion to the processes which regulate the hyperfine field behavior in these complex Co-Cu systems.