Logarithmic relaxation in the levitation force in a magnet-high T c superconductor system
- 4 May 1992
- journal article
- research article
- Published by AIP Publishing in Applied Physics Letters
- Vol. 60 (18) , 2294-2296
- https://doi.org/10.1063/1.107034
Abstract
The dynamic response of the levitation force between a permanent magnet and a bulk YBCO superconductor when subjected to a sudden motion‐induced step in the magnetic field has been measured. It is found that the levitation force relaxes logarithmically with time. Assuming that force and magnetization behave similarly, the rate of decay can be interpreted in terms of a thermally activated flux creep with a depinning activation energy of U0=0.20 eV. A replot of previously published results for melt‐quenched YBCO also demonstrates that also in this material the force relaxation is characterized by a logarithmic decay.Keywords
This publication has 6 references indexed in Scilit:
- Characterization of composite high temperature superconductors for magnetic bearing applicationsIEEE Transactions on Magnetics, 1991
- Defect independence of the irreversibility line in proton-irradiated Y-Ba-Cu-O crystalsPhysical Review Letters, 1990
- Rigid levitation and suspension of high-temperature superconductors by magnetsAmerican Journal of Physics, 1990
- Vortex motion and time dependent magnetic responses in high Tc superconductorsPhysica C: Superconductivity and its Applications, 1989
- Critical current density and pinning energy of an epitaxial YBa2Cu3O7-δ-filmPhysica C: Superconductivity and its Applications, 1989
- Theory of Flux Creep in Hard SuperconductorsPhysical Review Letters, 1962