Thin Magnetic Films on Metallic Substrates

Thin metal films are of great interest in material science for years. Very detailed information about growth mechanism, thin film composition, structure and morphology is reached by cross combination of macroscopic and microscopic techniques, in direct or momentum space, like scanning tunnelling microscopy, low energy electron diffraction, or Rutherford backscattering in combination with channelling. In particular, one has the possibility to focus on controlled growth of such films on structured surfaces of the substrate to achieve miniaturization which is of interest for future electronic, magnetic or optical devices. A recent example how information technology can benefit from the application of these methods is the discovery of the giant magneto resistance effect for magnetic information storage. As there is the need for storing more and more information in smaller and smaller areas, it I would be desirable to produce small magnetic clusters of well-defined size, distributed in a well-controlled way on a substrate. As this miniaturization requires stable, nanostructure template substrates with characteristic lengths in the nanometer range and the use of self-ordering thin magnetic films in the case of magnetic devices, the fabrication calls for new processing techniques which have to be further developed and optimized. Among others, a method to prepare such thin films. is the evaporation of the metal onto the substrate. Depending on thermodynamics and surface kinetics, there are many channels for the metallic atom to interact with the surface and the already deposited film, e.g., layer-by-layer growth (Frank-van-der-Merwe growth). The aim of the project is to study these different growth scenarios with the methods mentioned above. More specifically, we plan to investigate cobalt on self-organized vicinal gold substrate and thin platinum films on a nickel substrate. In the first situation, the aim is to take benefit of the self-organized gold substrate surface to produce small magnetic clusters of well defined size distribution in a well controlled way. The second situation corresponds to the formation of a metastable continuous thin film of magnetic alloy.