Point-Contact Spectroscopy on RuSr2GdCu2O8
  We present Point-Contact experiments on polycrystalline RuSr$_2$GdCu$_2$O$_8$ samples. The majority of tunneling curves shows a zero-bias conductance peak, which is modeled by assuming a d-wave pairing symmetry of the superconducting order parameter.The magnetic field dependence of the conductance spectra has been measured in very stable junctions. In some cases, due to the granularity of the samples, clusters of grains in series introduce peculiar features in the conductance spectra. 
Samanta Piano, Fabrizio Bobba, Filippo Giubileo, Antonio Vecchione,   Anna Maria Cucolo