Grosser, R. and Hoecherl, P. and Martin, A. and Niemetz, M. and Schoepe, Wilfried (2000) Vortex motion in superconducting YBa2Cu3O7-delta inferred from the damping of the oscillations of a levitating magnetic microsphere. JOURNAL OF LOW TEMPERATURE PHYSICS, 119 (5-6). pp. 723-742. ISSN 0022-2291
Full text not available from this repository.Abstract
The damping of the oscillations of a small permanent magnet (spherical shape, radius 0.1 mm) levitating between two parallel YBCO surfaces is measured as a function of oscillation amplitude and temperature. The losses in the samples (epitaxial thin films, bulk granular and bulk melt-textured) are analyzed in terms of oscillating shielding currents flowing through trapped flux lines whose motion gives rise to electric fields. We find dissipation to originate from different mechanisms of flux dynamics. At small amplitudes there is a linear regime described by a surface resistance varying from 10(-9) Omega for the bulk samples down to 10(-13) Omega for the thin films at low temperatures. With increasing amplitude various nonlinear regimes are observed, firstly collective pinning with diverging energy barriers, secondly in bulk samples above 85 K hysteric damping, and finally in thin films exponentially large losses which can be described by pinning energies vanishing linearly at large currents.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | II SUPERCONDUCTORS; SURFACE IMPEDANCE; SUPERFLUID-HELIUM; THIN-FILMS; TEMPERATURE; FREQUENCY; FIELD; DEPENDENCE; DYNAMICS; |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors > Prof. Wilfried Schoepe |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 26 Apr 2022 14:37 |
| Last Modified: | 26 Apr 2022 14:37 |
| URI: | https://pred.uni-regensburg.de/id/eprint/42445 |
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