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- Yang, Z.J., et al.
(författare)
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Study of flux motion in Bi-based superconductors by a pendulum
- 1992
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Ingår i: Journal of Superconductivity. - 0896-1107 .- 1572-9605. ; 5:2, s. 127-135
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Tidskriftsartikel (refereegranskat)abstract
- Using a computerized mechanical pendulum, we have studied the lateral magnetic flux motion of the Bi-based high-T c superconductors in the quasi-static magnetic field (0.1 Hz) for the range 1 μm to 0.35 mm. The effect of d.c. and a.c. transport currents on the flux motion has also been investigated. We argue that the lateral magnetic stiffness is a measure of the pinning potential of the fluxoids in the superconductors. The pinning energy barrier ε is estimated to be about 0.3 eV based on the stiffness measurements, which is comparable with the data from the YBa2Cu3O7-χ superconductors.
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- Johansen, T.H., et al.
(författare)
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Transition from elastic to dissipative motion in a magnet-high-Tc superconductor system
- 1991
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 70:12, s. 7496-7499
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Tidskriftsartikel (refereegranskat)abstract
- Using quasistatic harmonic excitations, we have measured the lateral force between a permanent magnet and a Bi-based ceramic high-Tc superconductor (HTSC) for lateral displacement amplitudes down to 1 µm. We find clear evidence for a transition from elastic (nondissipative) to inelastic interaction, and attribute the effect to flux pinning. The crossover amplitude can easily reach several micrometers, with the consequence that the lateral disturbance of a levitated magnet will decay to this amplitude, whereas further damping will be extremely slow. For applications of HTSCs in magnetic bearing systems this can be a very relevant aspect of the interaction, and it can set the limit for precision positioning of levitated objects
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