Dependence of critical current density on filament diameter in round multifilament Ag-sheathed Bi2Sr2CaCu2O<i>x</i> wires processed in O2

Abstract

Ag-sheathed Bi2Sr2CaCu2Ox round wires having 37 and 259 filaments, with filament diameters ranging from 11 to 100 μm, were fabricated by the oxide-powder-in-tube method. They were heat treated using step-solidification melt processing in air and pure O2. The transport critical current density was highest in wires processed in pure O2. It increased with decreasing filament diameter and was highest [165 000 A/cm2 (4.2 K, O T)] in wires with 11 μm filaments processed in O2.