An investigation of the structure of non-crystalline films of nickel, cobalt, and cobalt–phosphorus by electron diffraction

Abstract

Non-crystalline thin films of nickel and cobalt have been prepared by vapour deposition onto liquid-nitrogen-cooled substrates, whilst a cobalt–phosphorus alloy has been produced by electroless deposition. An electron diffraction study of these samples has been undertaken. The intensity profiles are found to be inconsistent with those calculated for models of f.c.c. or h.c.p. microcrystals. The most frequently occurring interatomic distances, obtained from the pair distribution functins, are similar to those given by the dense random packing of hard spheres. The nearest neighbour distance, in each of the samples, is slightly larger than that observed in the crystalline state, but the effective hard-sphere diameters, required to fit the experimental and theoretical pair distribution functions are approximately 5% smaller. It is concluded that a perfect dense random packing of atoms is not obtained since it is not possible to violate the distance of closest atomic approach observed in the crystalline state.