Flux pinning scaling behaviors of ultrafine multifilamentary NbTisuperconducting wires with Nb island-type artificial pins

摘要

In order to engineer composites for high critical current densities Jc, the establishment of an artificial pinning center (APC) composite technique based on the flux pinning mechanism is desired. For that purpose, we investigated temperature and magnetic field scaling behaviors on the flux pinning properties of several kinds of Nb island-type artificial pin wires. The temperature and magnetic field dependence of bulk pinning force densities Fp was evaluated from magnetization curves at 25-7.5K to exclude influences due to external effects such as filament sausaging. As a result it was found that the scaling law holds true in a wide range of temperatures and magnetic fields for all of the APC specimens, which is in contrast to α-Ti specimens. This result suggests that Nb island-type pinning is much stronger than ribbon-like α-Ti pinning