A study of dissipation mechanisms in high-T sub(c) superconductors

Magnetic losses and time dependence of magnetization for high-T sub(c), polycrystalline samples are being investigated. From magnetization data the flux-density-profile and critical-state-model parameters are obtained. The critical-state model has been modified to include the observed time dependence of magnetization which is described in terms of thermally activated flux-flow theory. The field and temperature dependences of the creep rate and the activation energy have been found and are discussed.