AVS 47th International Symposium
    Magnetic Interfaces and Nanostructures Tuesday Sessions
       Session MI+NS+NANO 6-TuM

Paper MI+NS+NANO 6-TuM9
Flux Lattice Imaging of a Patterned Nb Film with a Cryogenic Magnetic Force Microscope

Tuesday, October 3, 2000, 11:00 am, Room 206

Session: Magnetic Imaging I
Presenter: M. Roseman, McGill University, Canada
Authors: M. Roseman, McGill University, Canada
P. Grutter, McGill University, Canada
V. Metlushko, Argonne National Laboratory
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Using our cryogenic magnetic force microscope, we have investigated a superconducting Nb thin film, 100 nm in thickness with T@sub c@ ~6.6 K. The film is patterned with a square array (1 µm by 1 µm) of antidots, which serve as artificial pinning centers for magnetic flux. We have observed the flux lattice as a function of temperature (5.5 K - 6.6 K) and applied magnetic field, for field strengths up to 62.1 G, the third matching field (a matching field is one where the flux lattice spacing is commensurate with the antidot array). Evidence of flux dragging by the tip reveals information about both tip-vortex and vortex-vortex interactions, and provides an indication of localized sample pinning potentials. Force distance curves acquired at temperatures near T@sub c@ clearly demonstrate an observable Meissner force between tip and sample, and allow for an estimation of the value of the temperature dependent London penetration depth, @lambda@@sub L@(T).