We measure the dynamics of magnetic field penetration into thin-walled superconducting niobium cylinders. It is shown that magnetic field penetrates through the wall of a cylinder in a series of giant jumps with amplitude 1 - 2 mT and duration of less than a microsecond in a wide range of magnetic fields, including the vortex free region. Surprisingly, the jumps take place when the total current in the wall, not the current density, exceeds a critical value. In addition, there are small jumps and/or smooth penetration, but their contribution reaches only ≃ 20 % of the total penetrating flux. The number of jumps decreases with increased temperature. Thermomagnetic instabilities cannot explain the experimental observations.
Bibliographical noteFunding Information:
We thank J. Kolacek, G.I. Leviev, P. Lipavsky and V.A. Tulin for fruitful discussions. We are deeply grateful to Yu. A. Genenko for careful reading of the manuscript and very useful comments. We acknowledge unknown referee for his very useful remarks. This work was done within the framework of the NanoSC-COST Action MP1201. Financial support of the grant agency VEGA in projects nos. 2/0173/13 and 2/0120/14 are kindly appreciated. We acknowledge partial support of ERC grant number 335933.
© 2016 Elsevier B.V.
- Flux jumps
- Thin-walled cylinders