•F. Laube¹, G. Goll¹, H. v. Löhneysen^1,2, M. Fogelström³, F. Lichtenberg⁴, Z. Q. Mao⁵ und Y. Maeno^5
3Institute of Theoretical Physics, Chalmers University of Technology and Göteborg University, Sweden
⁴Experimentalphysik VI, Elektronische Korrelationen und Magnetismus, Institut für Physik, Universität Augsburg
⁵Department of Physics, Kyoto University, Japan
¹Physikalisches Institut, Universität Karlsruhe
²Institut für Festkörperphysik, Forschungszentrum Karlsruhe

Sr₂RuO₄, being isostructural to the high T_c superconductor (La,Sr)₂CuO₄, exhibits an unconventional superconducting ground state (T_c = 1.5 K). We present conductance measurements of normal conductor/superconductor point-contacts between Pt and Sr₂RuO₄ in zero and applied magnetic field in order to get information about the symmetry of the superconducting order parameter. In the superconducting state an Andreev bound state is formed at the superconductor surface, which is observed as a zero-bias anomaly in the spectra, i.e. dI/dV vs. V [1]. We compare measurements on different single-crystals with theoretical predictions within a self-consistent quasiclassical approach - possible up to the thermodynamic critical field - and conclude that a spin-triplet state is most favourable.