Interface properties in sequence permutated Fe―B―Ag multilayers

Fe–B–Ag multilayers have been prepared in two different sequences of the layers in order to reveal distinctness of “top” and “bottom” interfaces of each element in relation to the other two elements. Transmission electron microscopy analysis showed a much larger interface roughness for the Fe/B/Ag (i.e., Fe at bottom, Ag on top of B) than for the B/Fe/Ag sequence, which is mainly due to the different growth processes of Ag. For both sequence Fe and B layers of 2 nm thickness are continuous and solid state amorphization—similar to that observed in Fe/B multilayers—takes place during sample growth. Mossbauer spectroscopy measurements indicate that the amorphous interface has a broad bimodal concentration distribution for both layer sequence, but intermixing is larger at the Fe/B than at the B/Fe interface.