AC magnetization measurements are reported for a superconducting Pb (500 Å)/Cu (100 Å) film bilayer with a triangular lattice of antidots of diameter D = 0.35 μm and spacing d = 1.0 μm. Sharply peaked magnetization anomalies occur at applied DC magnetic fields Hn = nH1, where 1≤n≤3, and H1 = 24 Oe is the first "matching field" at which every antidot traps exactly one fundamental flux quantum Φ0. The peaked nature of the matching anomalies is similar to the behavior of Josephson networks (having d/D ≈ 1), but differs from more step-like structures observed in the magnetization of other patterned films with d/D ≫ 1. The n = 3, 4 matching anomalies successively disappear when the applied field is tilted away from the bilayer normal by 70-84°. The peaked magnetization, low transition temperature of 6.70 K, reduced angular stability of the flux lattice, and the absence of clear matching anomalies with n > 4, indicate that these properties are novel probes of a proximity effect between normal (Cu) and superconducting (Pb) film layers.
|Number of pages||7|
|Journal||Physica C: Superconductivity and its Applications|
|State||Published - Aug 15 2003|
Bibliographical noteFunding Information:
Research at the University of Kentucky was supported by US Department of Energy Grant #DE-FG02-97ER45653. Research at the Katholieke Universiteit Leuven was supported by the Flemish Fund for Scientific Research (FWO) and the Concerted Action (GOA) Programs. We thank Rik Jonckheere for the film mask fabrication, and Mr. Sergey Kryukov for help in manuscript preparation.
- Antidot arrays
- Flux pinning
- Proximity effect
- Superconducting thin films
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering