AVS 45th International Symposium
    Magnetic Interfaces and Nanostructures Technical Group Wednesday Sessions
       Session MI+NS-WeA

Paper MI+NS-WeA3
Imaging Current Flow in Polycrystalline Bi2Sr2CaCu2Ox Superconductors by Magnetic Force Microscopy

Wednesday, November 4, 1998, 2:40 pm, Room 324/325

Session: Nanoscale Magnetics: Imaging and Fabrication
Presenter: F. Král, ETH Zürich, Switzerland
Authors: F. Král, ETH Zürich, Switzerland
D. Perednis, ETH Zürich, Switzerland
D.A. Bonnell, The University of Pennsylvania
G. Kostorz, ETH Zürich, Switzerland
L.J. Gauckler, ETH Zürich, Switzerland
Correspondent: Click to Email
The measurement of magnetic fields induced by current flow can be used to visualize current transport paths in complex microstructures. Magnitudes of fields induced by currents typical of metallic conductors and of superconductors are within the range accessible by magnetic force microscopy. Finite element calculations indicate that conducting grains separated by as little as a hundred nm will be distinguished. The fields emanating from current in the complex textured microstructure of a Bi2Sr2CaCu2Ox based thick film in the superconducting state at temperatures below 60 K were clearly delineated. Magnetic field variations with the size and orientation of the textured grains that carry current were quantified. Obstructions to current flow are imaged.These measurements were accomplished on a commercial instrument modified to connect to a He cryostat and operate in medium vacuum.