DIRECT EVIDENCE OF PHASE-SEPARATION IN AS-DEPOSITED FE(CO)-AG FILMS WITH GIANT MAGNETORESISTANCE

High-resolution analytical electron microscopy (EM) on as-deposited di lute Fe(Co)-Ag films showed Fe(Co) clusters embedded in a Ag matrix su ggesting that these materials are not uniform substitutional alloys as it was previously believed. The cluster sizes observed from the EM im ages are slightly larger than those calculated from magnetization curv es, and this has been attributed to the interface roughness existing b etween the magnetic clusters and the nonmagnetic matrix. The magnetic properties and magnetoresistance values in these films are also discus sed relative to the high-resolution electron-microscopy results.