Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 48: Superconductivity: Heterostructures, Andreev Scattering, Proximity Effect, Vortices

TT 48.12: Talk

Friday, March 30, 2012, 12:30–12:45, H 2053

The role of thermal conductivity on the nucleation and propagation of magnetic flux avalanches — •Claudia Stahl¹, Sebastian Treiber¹, and Joachim Albrecht² — ¹Max-Planck-Institut für Intelligente Systeme, Heisenbergstraße 3, 70569 Stuttgart — ²Hochschule Aalen, Beethovenstraße 1, 73430 Aalen

Below a certain threshold temperature the critical state of superconducting thin films can get unstable, which results in large magnetic flux avalanches. In thin MgB₂ films with an inhomogeneous current density distribution both the nucleation and propagation of magnetic flux avalanches are highly favoured [1].

Magnetization measurements and magneto - optical imaging are used to characterize inhomogeneous MgB₂ thin films.

Avalanches occur when the thermal transport gets much slower than the transport by electric conductivity. Increasing the thermal conductivity by a gold cover layer leads to a suppression of the instabilities. It is investigated how the two steps of the avalanche process, nucleation and propagation, are influenced by the thermal conductivity in inhomogeneous MgB₂ thin films. We found that the gold layer in particular influences the initial phase of the avalanche formation.
S. Treiber, C. Stahl, G. Schütz, and J. Albrecht, Physical Review B 84, 094533 (2011).