Münster 1999 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 21: Postersitzung III: Hochfrequenzeigenschaften (1-4), Amorphe Systeme (5-9), Borkarbide (10-18), Quantenflüssigkeiten (19-25), Dünne Filme (26-49), Vortexdynamik, Pinning (50-63), M-I-Überg
änge, quantenkritische Ph
änomene (64-89)
TT 21.63: Poster
Donnerstag, 25. März 1999, 14:30–18:00, Foy
Evidence for Two Vortex Species in Nb Films in Parallel Field — •A. Pan1, R. Höhne1, P. Esquinazi1, M. Ziese2, and C. Assmann3 — 1Abt. Supraleitund und Magnetismus, Universität Leipzig, 04103 Leipzig — 2Department of Physics, University of Sheffield, Sheffield S3 7RH, United Kingdom — 3Cryosensoric Laboratory, PTB, 10587 Berlin
Using torque magnetometry we have investigated the transversal magnetisation of Nb thin films (thickness 120 nm and 1.2 µm) at different angles between applied field and main surface. The measurements at angles between 2o and 10o in the 120 nm thick film reveal anomalies at matching fields which are compatible with the arrangement of vortices in one or two in-plane rows. As expected from theory, these anomalies are not observed for the thicker film. For smaller angles and for both films, the observed response if compatible with the magnetisation of the perpendicular component that experiences a pinning barrier of geometrical origin for flux entry or exit. These results indicate the presence of two flux-line-lattices, parallel and perpendicular to the main surface of the film, in both Nb-films and support recently published speculations on their existence [1].
Supported by the DFG under INK 24/B1-1, Project H.
[1] A. Pan et al., Physica C 301, 72 (1998)