Isothermal magnetization curves of a superconducting Nb film perforated by a square lattice of Ni dots exhibit quasiperiodic instabilities below ∼4 K, with a field-dependent period equal to the first, second, or third matching fields. The instabilities are found in a range of applied fields well above the saturation matching value, and under conditions where a continuous Nb film with the same dimensions and magnetization remained stable. The results suggest that terraces of matched flux density exist at the border of a flux-depleted zone created by a geometric barrier near the film edge. Geometric effects may thus play an important role in determining the presence or absence of matching effects.
|Physical Review B - Condensed Matter and Materials Physics
|Published - 2000
Bibliographical noteFunding Information:
Research at the University of Kentucky was supported by the U.S. Dept. Energy Office of Basic Energy Science, Division of Materials Science, Grant #DE-FG02-97ER45653. Research at Northwestern University was supported by the National Science Foundation under the Materials Research Center Grant #DMR-9309061. Research at the University of Wisconsin was supported by the U.S. Dept. Energy Division of High-Energy Physics, Grant #DE-FG02-96ER40961 and the NSF MRSEC for Nanostructured Materials.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics