Atomic Structures and Magnetic Moments in Cu1-xAgx Alloy Matrix-Embedded Fe Nanoparticle Systems

Abstract

Changes in magnetism were investigated through control over the atomic structure for Cu1-xAgx alloy matrix-embedded Fe nanoparticles systems. Nanocomposite magnetic films were prepared using the low-energy cluster beam deposition (LECBD) technique under ultra-high vacuum (UHV) conditions. Fe nanoparticles were produced by gas aggregation source, while alloy matrices were produced by MBE sources. Extended x-ray absorption fine structure (EXAFS) experiments revealed that the Fe nanoparticles in pure Cu have fcc structure while retaining their bulk bcc structure in Cu1-xAgx alloy matrix. Also, a slight decrease in Fe-Fe interatomic distances was observed in the bcc Fe structure due to the compression in the alloy matrix. The magnetic moment of Fe was initially very low because of its fcc structure in the pure Cu matrix, however, increased ultimately to values of similar to 2.7 mu(B)/atom with increasing Ag content in the alloy matrix.