Point Contact Spectroscopy on RuSr2GdCu2O8

We report the first tunneling experiments performed by means of point-contact technique on the ruthenate-cuprate RuSr2GdCu2O8 (Ru1212) compound. Spectroscopy has been carried out on polycrystals characterized by superconducting transition at TC(? = 0) ? 26 K and magnetic transition at TM ? 133 K. A chemically etched copper tip has been used like normal counterelectrode. Very stable N-S contacts (N = Cu, S = Ru1212) have been obtained, clearly showing dI/dV spectra in the Andreev reflection regime. Temperature behaviour of the spectra has been measured in the range 4.2 K <= T <= 30 K. The dI/dV spectra seem to indicate important depairing effects in the Ru1212 and we discuss possible explanation.