Transition of flux pinning mechanism in mesoscopic NbTi/Nb/Cu superconductor

✍ Scribed by T Kitai; H Tsurumaru; M Higuchi; K Osamura; S Kikuchi; H Otsuka

• Book ID: 104111512
• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 351 KB
• Volume: 38
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/s0011-2275(98)00057-5

✦ Synopsis

The flux pinning mechanism in NbTi alloy including artificial pinning centres is studied by a NbTi/Nb/Cu multilayer composite. The ␣-Ti phase in NbTi alloy is the dominant flux pinning site when a period of superconducting plus normal layer thickness is higher than 1000 nm, while the artificial pinning centres of superconducting/normal boundaries are dominant when a period of the superconducting plus normal layer thickness is less than 100 nm. The maximum global pinning force (F pmax ) shows 14.8 GN m -3 at 4 T when the ␣-Ti phase is the pinning site. Alternatively, F pmax shows 23.7 GN m -3 at 1 T when an artificial normal Cu layer is the pinning site and the peak shifted to lower magnetic field. The critical temperature (T c ) reduces due to the proximity effect of both ␣-Ti phase and normal Cu layer. However, the layer thickness where T c starts to drop due to the proximity effect of ␣-Ti, is different from that for the normal Cu layer.