Evidence for a self-organized growth in granular Co/Al2O3 multilayers

By sequential deposition of thin layers of cobalt and alumina by sputtering, we have fabricated granular multilayers consisting of successive planes of nanosized cobalt clusters separated by alumina along the growth direction. Combining grazing-incidence small-angle x-ray scattering and transmission electron microscopy experiments, we show that, in a given range of thickness, the vertical arrangement of clusters from plane to plane is not random but shows a topology-induced self-organization. (C) 2000 American Institute of Physics. [S0003-6951(00)01620-X].