Giant flux jumps through a thin superconducting Nb film

TL;DR

This paper investigates the magnetic flux penetration in thin superconducting niobium cylinders, revealing giant flux jumps, their dependence on current and temperature, and oscillatory magnetic behavior inside the cylinder.

Contribution

It provides experimental evidence of giant flux jumps in superconducting Nb cylinders and analyzes their characteristics and temperature dependence.

Findings

Magnetic flux penetrates via giant jumps of 10-20 Oe amplitude.

Giant jumps occur when total current exceeds a critical value.

Number of jumps decreases as temperature increases.

Abstract

The dynamics of magnetic field penetration into thin-walled superconducting niobium cylinders is experimentally investigated. It is shown that magnetic field penetrates through the wall of a cylinder in a series of giant jumps with amplitude 10 - 20 Oe and duration of a few $\mu$s. The jumps take place when the total current in the wall, not the current density, exceeds some critical value. In addition there are small jumps and/or smooth penetration, and their contribution can reach 20% of the total penetrating flux. It is demonstrated that the magnetic field inside the cylinder exhibits several oscillations. The number of giant jumps reduces with temperature.