Structural and magnetic study of MBE-UHV evaporated (Fe/Y) multilayers

UHV evaporated (Fe/Y)(n) multilayers deposited into a MBE evaporator on MgO substrate were investigated by RHEED, GXRD, high-angle XRD, Fe-57 Mossbauer spectrometry at room temperature, and magnetization measurements at 300 and 5 K. The RHEED study was performed for (Fe 15 nm/Y) bilayers as a function of the Y thickness and for two (Fe/Y)(n=5) multilayers (t(Fe) = t(Y) = 0.5 nm and 1.0 nm) to determine the growth and the nature of the interfaces. The GXRD, high-angle XRD, Fe-57 Mossbauer spectrometry at room temperature, and magnetization measurements studies were performed as a function of the Fe layer thickness (t(Fe) = 0.5-6.0 nm) on (Fe t(Fe)/Y 1.0 nm)(n>5) multilayers deposited at 300 K. The Mossbauer paramagnetic doublet obtained at 300 K for t(Fe) = 0.5 nm, is characteristic of the Fe-Y interfaces. The crystallization of BCC Fe in the center of the Fe layers occurs for t(Fe), between 0.5 and 1.0 nm indicating that the Fe-Y interfaces are very sharp compared to other deposited (Fe/Y) multilayers. For (BCC Fe/Y) multilayers, the Mossbauer and the magnetization results indicate that the Fe-Y interfaces thickness remains constant as t(Fe), increases. In average, only one monolayer of Fe is involved at each Fe-Y interface. (C) 2003 Elsevier B.V. All rights reserved.