Atomic structure in magnetic cluster assembled Fe/Co films as determined from extended absorption fine structure

The atomic structure of nanocomposite Fe/Co films has been studied using synchrotron radiation. Films in which Co nanoclusters are embedded in an Fe matrix, and films where Fe nanoclusters are embedded in Co, are both investigated. The samples were prepared by co-deposition using a gas aggregation cluster source. Co and Fe K edge EXAFS measurements were used to probe the atomic structure within the Co and Fe nanoclusters respectively as a function of cluster volume filling fraction. In an Fe matrix, the Co clusters are found to adopt a bcc structure across the composition range investigated; at the highest cluster filling fraction of nearly 40%, the atomic structure still does not revert to hcp, the crystal structure in bulk Co. Fe nanoclusters embedded in Co retain the bcc structure of bulk Fe.