DIFFUSION AMORPHIZATION AND INTERFACE PROPERTIES OF FE-B MULTILAYERS

The interface of Fe-B multilayers was studied by Mossbauer spectroscop y, X-ray diffraction and transmission electron microscopy. The interfa ce region is amorphous and consumes 2 nm from the iron layer. The same hyperfine field distribution is observed within the amorphous interfa ce when the individual layer thicknesses exceed the width of the inter face. The width of this distribution is much larger than those measure d in amorphous Fe-B alloys and the excess width is attributed to conce ntration distribution along the interface. On the contrary, the amorph ous component in samples with smaller layer thicknesses is more homoge neous as deduced from the hyperfine field distributions, and the hyper fine parameters depend on the ratio of the iron and boron layer thickn esses, Solid state amorphization during the sample deposition is assum ed to account for this behavior. Diffusion amorphization is also detec ted when low-temperature heat treatment of the large layer thickness s amples is performed. Single-phase amorphous alloy is formed in both ca ses in a limited concentration range around 40 at% boron in agreement with the predictions of free-energy diagrams.