Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 64: Superconductivity: Heterostructures, Andreev Scattering, Vortex Physics
TT 64.8: Vortrag
Donnerstag, 14. März 2013, 17:00–17:15, H21
The relation between electrical fields and flux avalanches in MgB2 films — •Sebastian Treiber1, Claudia Stahl1, Soltan Soltan2,4, and Joachim Albrecht3 — 1Max-Planck-Institut für Intelligente Systeme, Heisenbergstrasse 3, 70569 Stuttgart, Germany — 2Max-Planck-Institut für Festkörperfoschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany — 3Hochschule Aalen, Beethovenstrasse 1, 73430 Aalen, Germany — 4Physics Department, Faculty of Science, Helwan University, 11792-Cairo, Egypt
The critical state in superconductors with strong pinning is inherently unstable. In most metallic materials, there is a threshold temperature below which large flux jump can destroy the critical state locally or even globally. The basic mechanism is a chain reaction due to local overheating. Thus, heat capacity and conductivity are important quantities in this process. Here, we want to focus on another important parameter, namely the electrical field. Large flux jumps, which are often referred to as flux avalanches, are triggered by a threshold value of the electrical field. Basically, one would expect the change of the external magnetic field Ḣext as a direct source for electrical fields. Though a change of Hext is necessary to trigger an avalanche, the mechanism is more complex which is shown by means of magneto-optical, magnetization and transport measurements.