Assessment of the local supercurrent densities in long superconducting coated conductors

Abstract

The authors report on measurements of the local supercurrent density in long Y1Ba2Cu3O7−δ based coated conductors by the magnetoscan technique. Significant inhomogeneities were found, which are well resolved by the resulting magnetic field map. A single central line scan along the length of the conductor reflects the inhomogeneities over the entire width of the sample, thus offering the possibility of very fast characterization. Modifying the applied field leads to different results highlighting either the overall critical current or details of the defect structure. In addition, numerical simulations of the current dynamics were carried out for a qualitative and quantitative interpretation of the results.

Scanning Hall-probe microscopy system for two-dimensional imaging of critical current density in RE-123 coated conductors

“…Furthermore, TAPESTAR TM cannot give information about the inhomogeneity in the width direction of a CC with an enough spatial resolution, while such information is very important in processing for multifilamentary CCs as well as in cutting for finer CCs. Magnetoscan [5,6] may overcome these problems. However, magnetoscan also needs a careful calibration for a quantitative characterization because the electromagnetic behavior in a sample strongly depends on the scanning speed, the distance between the sample and the permanent magnet and so on.…”

Scan Techniques for Coated Conductors

“…If necessary, also the position of the Hall probe can be changed. All of these modifications are presently studied by numerical calculations [4], in order to analyze the local current and field distributions.…”

Contactless measurement of critical current of high temperature superconductor tape by magnetic circuit

“…By detecting or interacting with the fields generated by supercurrents, we could derive an equivalent I c . [2][3][4][5][6][7] Of all contacless methods, magneto-optical imaging gives the best space resolution, but is not suitable for a reel-to-reel measurement due to low speeds. 2 The Hall sensor method, which uses a piece of sensor or array above the surface of HTS tapes to detect fields generated by supercurrents, is the most commonly developed into the reel-to-reel measurement.…”

“…This method was independently developed by several groups and formed different technical aspects. 3,5,7 However, the Hall sensor method usually meets difficulty while measuring YBCO tapes with magnetic substrates due to interference from the substrates. An inductive method, which detects the third harmonic signal in response to an ac exciting field, could tackle this problem.…”