Preparation And Analysis Of Epitaxial Fe Monolayers Buried In Pd

Pd almost fulfils the Stoner criterion to be ferromagnetic. In order to understand effects of ferromagnetic inclusions in Pd it is of great interest to study in detail the influence of an ultrathin Fe layer in Pd. Here we report on the preparation and characterization of epitaxial Pd containing Fe layers of a few monolayer thickness. The growth procedure on Ag buffered GaAs(001) substrates was optimized by in-situ Low Energy Electron Diffraction (LEED) and Auger Electron Spectroscopy (AES) to obtain chemical purity and monocrystallinity of the layers with smooth interfaces. By using a variable deposition temperature during the growth of the first Pd layer on the Ag buffer we were able to avoid interdiffusion between Ag and Pd. X-ray- and polarized neutron reflectometry revealed a very well defined interface between the Pd and Fe on top, but an intermixing zone between Fe and Pd on top. With decreasing Fe layer thickness we have observed an increasing magnetization compared to bulk Fe moments.