Crossover behaviors in magnetoresistance oscillations for Nb thin film with rectangular arrays of antidots
1 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences P.O. Box 603, Beijing 100190, PRC
2 INPAC-Institute for Nanoscale Physics and Chemistry, KU Leuven - Celestijnenlaan 200D, B-3001 Leuven, Belgium, EU
Received: 18 April 2012
Accepted: 8 July 2012
Superconducting Nb thin films with rectangular arrays of submicron antidots (holes) have been systemically investigated by transport measurements. A series of crossover behaviors is found in magnetoresistance oscillations, corresponding to three different superconducting states: the wire network-like state, the interstitial vortex state and the single-loop–like state. These states are identified by the field intervals and hysteretic effect. The crossover fields between them are found to be both temperature and geometry dependent. Furthermore, in dense arrays, the saturation number is distinctly larger than the theoretical calculation for a single insulating inclusion. Our results indicate that in the process of magnetic field penetration into nanostructured superconductors, the order parameters are strongly modulated and finally localized near the edges, resulting in changes of oscillation modes.
PACS: 74.78.Na – Mesoscopic and nanoscale systems / 74.81.Fa – Josephson junction arrays and wire networks / 74.25.F- – Transport properties
© EPLA, 2012