Alloy formation at the Fe-on-Nb and Nb-on-Fe interfaces

Nb/Fe/Nb vacuum evaporated trilayers were studies by X-ray reflectometry, Rutherford backscattering spectrometry and Mossbauer spectroscopy in order to obtain information on the properties of the Fe-on-Nb and Nb-on-Fe interfaces. According to the Mossbauer analysis the interfaces are rather sharp; chemical mixing forms less than 1 nm thick Fe-rich interfaces at both sides of the Fe layer. Comparison to X-ray reflectometry and Rutherford backscattering spectrometry results indicate that interface alloying and geometrical roughness equally contribute to the element distribution across the Fe and Nb layers.