V.F. Rusakov

The structure of vortex matter avalanches in a niobium plate

We observed a threshold for enter of the huge flux avalanches in the shielding experiments (in other words, for the increasing of the screening properties of superconductor before flux jump). We also found a threshold for exit of residual flux in the trap experiments. In any case, the value of threshold achieved up to 15% of the full volume of the flux jumps. The results of our experiment allow to analyse quantitatively inertial properties of the vortex matter using the balance of energy.

Oscillation mode in the screening properties of Nb–Ti plate as a result of flux jumps

Abstract Using of the Hall probe, we have monitored oscillations of the magnetic flux induction at the surface of the Nb–Ti sample as a result of the huge avalanche. We interpret the observed oscillations as a result of the existence of the wave of density in the vortex matter, i.e. we consider this phenomenon as displaying the inertial property of the vortex matter.

Role of the field dependence of the heat capacity for the flux jump process in HTSC materials

Abstract Magnetization and magnetostriction loops were calculated in terms of the Kim–Anderson model incorporating the flux jump instability criterion and taking into account magnetic field and temperature dependencies of the heat capacity of YBaCuO. Regions in the H – T diagram where flux jumps occur were determined. The stabilizing role of the specific heat for the critical state of the material was observed.

Analysis of H-T flux jump diagrams from different critical state models

The magnetic field - temperature ranges where the critical state for type II superconductors is unstable were calculated in terms of the following pinned critical state models: the Kim-Anderson model, the exponential model and the linear model. Comparative discussion of H-T diagrams of flux instabilities is presented.

Peak effect and giant flux jumps in hard superconductors: the problem of “islands” jumps on H-T diagram

Abstract Magnetic properties of superconductors with peak effect were investigated both experimentally and theoretically in frames of the critical state model which incorporates the flux jump instability criterion. Theoretical analyses show some “forbidden” band for flux jumps on the magnetic field axis. Features of H-T diagrams of instability of superconductors with peak effect are discussed.