Investigation of interface magnetic moment of Fe/Ge multilayer : A neutron reflectivity study

Fe∕Ge multilayer sample was grown on Si(100) substrate by rf sputtering. X-ray diffraction shows that the Fe layers are polycrystalline whereas the Ge layers are amorphous in this sample. X-ray reflectometry and unpolarized neutron reflectometry techniques have been used to determine the structural parameters viz. individual layer thickness, interface roughness, and the density of the layers. Polarized neutron reflectometry has given magnetic moment depth profile for the multilayer thin film. There is a large reduction in magnetic moment for Fe atom on an average in the Fe layers. Magnetic moments of Fe at the interfaces are lower compared to the regions away from the interfaces. There is an asymmetry between magnetic moments at Fe on Ge interfaces and Ge on Fe interfaces as well. Superconducting quantum interference device measurement indicates that the sample is ferromagnetic at room temperature with a lower magnetic moment compared to bulk iron.