Hysteresis magnetoresistance and edge superconductivity in Nb film with diluted square array of holes

• Published in: Superconductor science & technology Vol. 30; no. 11; pp. 115016 - 115022
• Main Authors: He, S K, Zhang, W J, Han, X F, Qiu, X G
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.11.2017
• Subjects: matching effect; periodic pinning array; surface superconductivity; wire network
• ISSN: 0953-2048; 1361-6668
• DOI: 10.1088/1361-6668/aa8f90

We investigated the transport properties of a superconducting Nb film with a diluted square array of holes, in which one fourth of the sites were removed from the original square lattice. The edge-to-edge separation of the holes in the sample is comparable to the superconducting coherence length, resulting in a system similar to multi-connected superconducting islands. Three regions in magnetoresistance ( R ( H ) ) curves can be identified. In the low field region, fluxoid quantization leads to fine structures in R ( H ) and T c ( H ) curves. At higher fields, the entering and leaving of interstitial vortices results in a novel field and temperature dependent hysteresis. At even higher fields, weak oscillations in resistance were observed due to edge superconductivity of inter-hole biconcave thin necks and Little-Parks effect. Moreover, the edge state results in a remarkable field induced narrowing of superconducting transition width.