Intrinsic Josephson Effects in the Magnetic Superconductor RuSr2GdCu2O8
  We have measured interlayer current transport in small sized RuSr2GdCu2O8 single crystals. We find a clear intrinsic Josephson effect showing that the material acts as a natural superconductor-insulator-ferromagnet-insulator-superconductor superlattice. So far, we detected no unconventional behavior due to the magnetism of the RuO2 layers. 
T. Nachtrab, D. Koelle, R. Kleiner, C. Bernhard, C. T. Lin