MAGNETIC IRREVERSIBILITY LINES IN PR2-XCEXCUO4-DELTA SINGLE-CRYSTALS

We present measurements of the ac-susceptibilty as a function of frequ ency and superimposed magnetic dc-fields of electron doped high-T-c-su perconductors Pr2-xCexCuO4-delta. The critical current density is deri ved from magnetic hysteresis loops. We observe a frequency shift of th e irreversibility line similar to what is usually observed in p-type h igh-T-c-superconductors. For the critical current we observe a purely exponential field dependence over a broad temperature and field range.