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TT: Tiefe Temperaturen
TT 6: Postersitzung I: Mesoskopie(1-21), amorphe Metalle und Defektsysteme(22-29), Kryotechnik, Kernmagnetismus(30-37), festes N2(38), Quantenflüssigkeiten und -kristalle(39-48), dünne supraleitende Filme(49-68), schwere Fermionen und Kondosysteme(69-92), Fullerene(93-94)
TT 6.15: Poster
Dienstag, 18. März 1997, 09:30–13:00, Z1
Phase Boundary for a Mesoscopic Superconducting Square Loop — •V. M. Fomin1,2, V. R. Misko1,3, J. T. Devreese1, and V. V. Moshchalkov4 — 1Departement Natuurkunde, UIA, Universiteitsplein 1, B-2610 Antwerpen, Belgium — 2Department of Theoretical Physics, SUM, Str. Mateevici 60, MD-2009 Kishinev, Republic of Moldova — 3Institute of Applied Physics, ASM, Str. Academiei 5, MD-2028 Kishinev, Republic of Moldova — 4Lab. voor Vaste-Stoffysica en Magnetisme, KUL, Celestijnenlaan 200 D, B-3001 Leuven, Belgium
The Ginzburg-Landau equations are solved self-consistently for a mesoscopic superconducting square loop. It is shown that the inhomogeneous distribution of the amplitude of the order parameter inside the loop leads to the appearance of certain areas (e. g., in the corners) which sustain much higher applied magnetic fields as compared to the “body” of the loop. The interplay between the square symmetry of the loop and the cylindrical symmetry of the magnetic field results in different Little-Parks oscillatory superconducting phase boundaries which correspond to various phase boundary definitions. The criterion to define the phase boundary magnetic field (H)–temperature (T) is formulated; it allows to obtain a good agreement between the calculated H(T) curve and the experimentally observed one in the mesoscopic aluminum loop [1]. This work is supported by NFWO, WOG (Belgium).
[1] V. V. Moshchalkov, L. Gielen, C. Strunk, R. Jonckheere, X. Qiu, C. Van Haesendonck, Y. Bruynseraede, Nature 373, 319 (1995).