Enhanced critical current density in multifilamentary NbTi/Cu superconductors with highly aligned artificial pinning center

Abstract

Three forms of Nb artificial pinning centers (APC), that is barrier-shaped, layer-shaped and island-shaped pins, were introduced into multifilamentary NbTi/Cu superconductors, and the wires were rolled into different aspect ratios. The critical current densities ( J c∥) were enhanced at high aspect ratio of tape when the broad face of the NbTi/Cu tapes is parallel to the magnetic field for all three types of APC tapes. The highest critical current density increased to more than 4010 A/mm 2 at 5 T, 4.2 K in NbTi/Cu tapes with Nb island-shaped. Moreover, the critical field ( H c2) were also changed in multifilamentary NbTi/Cu tapes with highly aligned Nb artificial pinning centers in different forms when the tapes have different aspect ratio as well as have different orientation (parallel and perpendicular) with magnetic field.