Publication Details

Golovchanskiy, I. A., Pan, A. V., Johansen, T. H., George, J., Rudnev, I. A., Rozenfeld, A. & Fedoseev, S. A. (2018). Origin of magnetic flux-jumps in Nb films subject to mechanical vibrations and corresponding magnetic perturbations. Physical Review B: Covering condensed matter and materials physics, 97 (1), 014524-1-014524-7.


In this paper the origin of flux-jumps in Nb thin films is established during magnetization measurements using a vibrating sample magnetometer (VSM). Magnetization measurements of the flux avalanche activity show its strong dependence on frequency and amplitude of VSM vibration. In particular, under certain conditions the vibrations induce a transition from a stable superconducting critical state to an undercritical state, accompanied by the 20-fold drop in the magnetic moment. These features allow the elucidation of the origin of the flux-jumps. In contrast to the commonly assumed thermomagnetic instabilities to be responsible for the flux-jumps in Nb films, our results provide solid support for an alternative explanation being due to criticality-built instability well represented by a sandpile. Considering properties of the flux-flow during a flux avalanche regime allows us to estimate nonuniformity of a magnetic field in a VSM sample space developed as a result of vibrations.

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