Dynamics of magnetic flux penetration into thin-walled cylinders

  Menachem Tsindlekht[1]  ,  Valery Genkin[1]   ,  Israel Felner[1]  ,  Felix Ziedes[1]  ,   Nadav Katz[1]  ,   Štefan Gazi[2]  ,  Štefan Chromik[2]  ,  Jan Kolaček[3]  ,  Miroslav Maryško[3]  
[1] [The Racah Institute of Physics, the Hebrew University of Jerusalem, 91904 Jerusalem, Israel
[2] The Institute of Electrical Engineering SAS, Dubravska cesta 9, 84104 Bratislava, Slovakia
[3] Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 16253 Praha, Czech Rep.

We report the results of an experimental study the dynamics of magnetic flux penetration into thin-walled Nb cylinders in a swept magnetic field. Nb film was deposited on the four sides of two sapphire substrates with cross section sizes 3 by 1.4 mm, but with different lengths: 7.5 and 21 mm. The Nb cylinders film thickness was 100 nm. The measurements were performed using pick-up coil method. It is shown that magnetic field penetrates through the cylinder wall in a series of giant jumps under magnetic fields lower and above Hc1 [1]. The time dependence of the internal magnetic field during the jump was calculated. It turns out that the internal field oscillates. Magnetic field and current density distribution in thin-walled cylinders of finite length was calculated numerically. Results showed that these jumps could be the manifestation of a field singularity at the end sides of a hollow superconducting cylinder.


[1] M.I. Tsindlekht, V.M. Genkin, I. Felner, F. Zeides, N. Katz, Š. Gazi, and Š. Chromik, “Giant flux jumps through a thin superconducting Nb film in a vortex free region”, Physica C 529, 1 (2016).