Structural transition in Cu/Fe multilayered thin films

摘要

Microstructural development of Fe and Cu in Cu/Fe multilayers of layer thickness 1.5-10 nm prepared on Si, Ge, and MgO substrates by ion beam sputtering were studied using XRD and cross-sectional TEM. High-angle x-ray results show an fcc Cu structure and a distorted bcc structure in the Fe layers at 5 nm-layer-thickness and smaller, and bcc Fe(110) and fcc Cu(111) peaks in the 10 nm-layer-thickness samples. Low-angle XRD indicates that the layers in the samples grown on MgO substrates have a more uniform and smooth layered structure than the multilayers grown on Si and Ge substrates, which results from larger grains in the MgO substrate samples for the same layer thickness. Relations among growth, microstructure, and interfaces with layer thickness are discussed.