Point-contact spectroscopy on RuSr2GdCu2O8

We present point-contact experiments on polycrystalline RuSr2GdCu2O8 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. (c) 2005 Elsevier Ltd. All rights reserved.