Microscopic flux density of small and dendritic flux jumps in MgB2 thin films

Abstract

In contrast to the detailed study on macroscopic vortex avalanches, the development of microscopic small flux jumps and dendritic branches during the growth of an avalanche in a MgB2 thin film with changing temperature and magnetic field is not well studied. Our study of the two phenomena shows that the number and the size of the small flux jumps and the maximum flux density critically depend on the width of the rectangular thin film with dimensions 3 mm x width for film width ranging from 0.2 to 1.6 mm. We also found that when the ratio between the maximum field density and the applied flux was below 1, dendrites do not exist.