In Situ Quantitative Measurement of Structural and Magnetic Properties of Nano-Structured Cobalt Films and Wires

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9701488 Wang This project examines the structure and magnetic properties of epitaxial Co/Cu/Co trilayers and Co OwiresO prepared by molecular beam epitaxy (MBE). The Co and trilayer films are grown on flat and vicinal (step bunched) silicon (111) surfaces, respectively. The parameters describing the interface roughness and mixing of these Co nanostructures are determined quantitatively in situ from the angular profile measurement of diffraction beams using high resolution, low energy electron diffraction complemented with scanning electron microscopy. The coercivity, magnetic anistropy, exchange coupling, magneto resistance, and magnetic inhomogeneity are obtained in situ from the surface magneto-optic Kerr effect (SMOKE), ferromagnetic resonance, and the Van der Pauw method. Atomic force microscopy and magnetic force microscopy provide important information on morphology and magnetic domain wall structures. In addition the temperature dependence and magnetic stability of these nanostructures are studied. %%% The quantitative relationship between interface roughness and magneto resistance and magnetic exchange coupling and their temperature dependence will permit an optimization of the trilayer that has the largest and thermally stable magneto resistance at very low magnetic fields. Such materials have applications in magnetic read heads for ultrahigh density hard disk drives. ***