Modified magnetoscan technique for assessing inhomogeneities in the current flow of coated conductors – Theory and experiment

• Published in: Physica. C, Superconductivity Vol. 460-462; no. 1; pp. 158 - 161
• Main Authors: Zehetmayer, M., Fuger, R., Hengstberger, F., Kitzmantel, M., Eisterer, M., Weber, H.W.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.09.2007; Elsevier Science
• Subjects: Coated conductors; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Critical currents; Exact sciences and technology; Magnetoscan; Numerical simulation; Physics; Properties of type I and type II superconductors; Superconductivity; Transport properties (electric and thermal conductivity, thermoelectric effects, etc.); Coated conductors; Numerical simulation; Magnetoscan; Critical current density; Digital simulation; High-Tc superconductors; Magnetic field effects; Measuring methods; Transport processes; Maxwell equations; Magnetic measurement
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/j.physc.2007.04.075

The magnetoscan technique was recently introduced to investigate local inhomogeneities of large high Tc superconductors without destroying them. Local currents are induced by a small permanent magnet moving slightly above the sample surface. The magnetic field of these currents, which depend on the local material properties, is measured by a Hall probe. We show that the technique can be successfully applied to coated conductors. Inhomogeneities and defects are easily detected by significant changes in the magnetoscan signal. To confirm our interpretation of the experiment, numerical simulations, based on Maxwell’s equations, were carried out. We calculate the current flow and the magnetoscan signal for different experimental setups and critical current densities. Inhomogeneities were introduced by assuming a position dependent critical current density. Good agreement between experiment and theory is obtained.