Magnetization curve and its relaxation of Bi-Sr-Ca-Cu-O films

We have measured magnetization and its relaxation of Bi-Sr-Ca-Cu-0 oriented films for wide ranges of temperature and field. The magnetization curves measured in the field along c-axis exhibit that the field of irreversibility limit, H 0 (T), deviates from a (1-T/T c ) 3/2 dependence below 40 K. The magnetization decays logarithmically with time in relatively weak field, whereas the simple logarithmic decay doesn’t hold in fields near H 0 .