Nonmonotonic crystallite-size dependence of the lattice parameter of nanocrystalline nickel

A nonmonotonic crystallite-size dependence of the lattice parameter of ultrathin, nanocrystalline Ni films, i.e., lattice contraction followed by lattice expansion with decreasing crystallite size, was observed using in situ x-ray diffraction stress measurements combined with a dedicated thermal treatment called “loop annealing.” The expected lattice contraction with decreasing crystallite size was found for nanocrystalline Cu and nanocrystalline Pd.