The influence of defects on the structure of the intermediate state in superconductive lead

The intermediate state structure of superconductive lead at 4·2°K has been studied by a refined Bitter technique. The results suggest that the distribution of magnetic flux in 99·99% pure lead is influenced by groups of dislocations formed by mechanical deformation and subsequent room temperature annealing. Non-uniform distributions of impurities and second phase particles appear to influence the recrystallization structures, giving rise to non-uniform distributions of dislocations, and thus have an indirect influence on the intermediate state structure.