Conventional x-ray diffraction failed to provide correct information on all
oying of materials made of elements with close lattice parameters, even for
elements commonly accepted to have miscibility. Using anomalous x-ray scat
tering, we showed that nanostructured NiCo films did not necessarily form s
olid solution as expected from their phase diagram or suggested by the resu
lts of conventional x-ray diffraction. (C) 1999 American Institute of Physi
cs. [S0003-6951(99)02542-5].