Diameter-dependent critical current densities for superconducting Bi-2212/Ag wires
Progress in the development of Bi-2212/Ag monocore superconducting wires fabricated by the powder-in-tube method is described. For short specimens of 0.65 mm diameter, maximum critical current densitites of up to 120,000 A/cm2 (B = 0) and 40,000 A/cm2 (B = 12T) are achieved at 4.2 K. The heat treatment conditions leading to the highest critical current densities are found to depend on the wire diameter. An increasing thickness of the silver sheath may be responsible for a retarded release of oxygen from the core before the superconductor is partially molten. Evidence for grain alignment in a thin layer at the interface to the silver of typically 10-20 micron thickness is investigated using scanning electron microscopy. A model which explains the observed scaling behaviour of the critical current density with the wire diameter is described and, using this model, the critical current density in the interfacial region is estimated.
Bibliographic Reference: Article: Cryogenics, Vol. 34 (1994) No. 10, pp. 805-811
Record Number: 199510059 / Last updated on: 1995-01-10
Original language: en
Available languages: en