Effect of filament size on superconducting properties of the Bi-2212 ROSATwire

We have investigated the effects of the filament size on superconducting pr operties using samples with various filament sizes and wire diameters. It i s revealed that the filament thickness is the most important dimensional fa ctor for superconducting properties of the ROSATwire (rotation-symmetric ar ranged tape-in-tube wire) and that a maximum J(c) was obtained for a filame nt thickness around 10 mum. A 660- or 456-filament structure would be suita ble for the wire with diameter of 1.5-2 nun which are commonly used in magn ets, because this would provide the optimum filament thickness. (C) 2001 El sevier Science B.V. All rights reserved.