Critical currents and flux pinning in Ag stabilized high Tc superconductor wires

✍ Scribed by J. Tenbrink; K. Heine; H. Krauth

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 530 KB
• Volume: 30
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(90)90169-d

✦ Synopsis

Y1Ba2Cu307_x and Bi2Sr2CalCu208+ x Ag sheathed high Tc superconductor wires have been prepared using the powder in tube technique. Characterization of wire specimens was performed mainly by measuring critical current densities at 77 K and 4.2 K, as well as by a.c. susceptibility measurements. Whereas the critical current density in Y1Ba2Cu307_x/Ag wires is limited by weak links, there are virtually no weak links present in Bi2Sr2CalCu2Os+x/Ag wires. Above = 20 K, critical current density in this material seems to be limited by flux creep. At lower temperatures flux creep becomes insignificant. At 4.2 K critical current densities of up to 5.7 × 104 A cm-2 in zero magnetic field and of up to 1.5 × 104 A cm-2 in a field of 26 T could be achieved, rendering possible the use of this material for very high field application. The results will be compared with those obtained on conventional metallic Nb-Ti superconductor wires. Flux pinning in these materials will be discussed, based on a model of direct summation of elementary pinning forces.