Vortex microavalanches in superconducting Pb thin films

[摘要] Local magnetization measurements on 100-nm type-II superconducting Pb thin films show that flux penetration changes qualitatively with temperature. Small flux jumps at the lowest temperature gradually increase in size, then disappear near T=0.7T(c). Comparison with other experiments suggests that the avalanches correspond to dendritic flux protrusions. Reproducibility of the first flux jumps in a decreasing magnetic field indicates a role for defect structure in determining avalanches. We also find a temperature-independent final magnetization after flux jumps, analogous to the angle of repose of a sandpile.

[发布日期] 2003-12-01

[关键词] FIELD PENETRATION;AVALANCHES;MAGNETIZATION;INSTABILITY;GROWTH