Hysteresis losses in BSCCO(2223)/Ag multifilamentary tapes

In order to investigate hysteresis losses on Ag-sheathed BSCCO(2223) multifilamentary tapes, we perform hysteresis loop measurements, with the external magnetic field He perpendicular to the tape surface, for different sweep rates of the magnetic field and at different temperatures T. The experimental results show a sweep rate dependence, equivalent to a frequency dependence of the hysteretic losses. In order to consider the role of the thermally activated flux creep in the losses we numerically solve the diffusion equation for the magnetic field B inside a superconducting slab. For magnetic field lower than 2.5 T and in the temperature and frequency range investigated, the numerical and experimental results show that the losses have a logarithmic dependence on the sweep rate. For higher field and increasing temperature, the logarithmic behaviour is no longer observed at higher frequencies. 2002 Elsevier Science B.V. All rights reserved.