Cobalt and nickel cluster-assembled thin films obtained by low-energy cluster beam deposition

Abstract

Nanostructured films of cobalt and nickel have been prepared using the low-energy neutral cluster beam deposition technique on various substrates. The nucleation-and-growth process of the films has been studied by in-situ electrical conductivity measurements and transmission electron microscopy observations. Complementary results obtained from X-ray diffraction and absorption measurements on films 100 nm thick confirm the nanostructured morphologies of both Co and Ni films consisting of a random stacking of well crystallized fcc grains having a diameter of around 3–4 nm. In terms of magnetic properties the granular structure leads to films which roughly behave like amorphous ferromagnets but with local order of the extent of a grain. From magnetization measurements and ferromagnetic resonance experiments which showed spin-wave oscillations, the magnetic parameters characteristic of the cluster-assembled films (i.e. magnetocrystalline anisotropy and intergrain exchange coupling energies) have been determined.