Transport and magnetic properties of Ag-sheathed Bi-2223 tapes

Bi-2223 tapes were investigated by transport and magnetic measurements. Two different regimes concerning the field dependence of the critical current density J/sub c/ are obtained. At T/spl ges/6 K J/sub c/ follows an exponential law. From analysis of magnetic relaxation measurements by means of distributions of activation energies an explanation of the low temperature behaviour of J/sub c/, in terms of a change in pinning behaviour is possible.<>