PULSED MAGNETIC-FIELD EFFECTS IN HIGH-TEMPERATURE SUPERCONDUCTORS

The use of fast rise-time pulsed magnetic fields (10E8 Oe s-1) in the study of magnetic properties of high temperature superconductors (HTSC ) is described. Comparisons are made with the conventional low tempera ture superconductor niobium. Pulsed field techniques are shown to be p articularly useful in observing flux trapping and hysteresis in materi als. A weak dependence upon pulse rise-times is found for the time for field penetration to the center of HTSC samples but not for Nb. These results are shown to be consistent with theories of flux flow phenome na in superconductors.