Characterisation of advanced technical superconductors

•Marion Kläser, Frank Hornung, Hanno Leibrock, Hans Müller und Theo Schneider
Institut für Technische Physik, Forschungszentrum Karlsruhe GmbH, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen

By means of the high magnetic field test facilities in the high-field laboratory (HFL) at the Forschungszentrum Karlsruhe the superconducting properties of low (NbTi, Nb3Sn) and high (Bi2212, Bi2223) temperature superconductors were investigated at 1.8, 2.2 and 4.2 Kelvin in magnetic fields up to 20 Tesla. The electric field-current relation, E(I), is examined resistively using a high resolution four-point measurement technique. Detailed error analysis ensure the significance of the E(I)-characteristics and of the resultant critical current Ic and n-value. The outcomes are used e.g. to compare commercial conductors and to optimise the heat treatment of binary and ternary A15-superconductors.

These investigations are the base for the development and construction of superconducting high-field magnets for experimental high-field test facilities and new generations of NMR spectrometers.