15. We highlight the advantages of using point-contact spectroscopy in multigap superconductors like MgB₂, both as a fundamental research tool and as a non-destructive diagnostic technique for the optimization of thin-film characteristics. We first present some results of crucial fundamental interest obtained by directional point-contact spectroscopy in MgB₂ single crystals, for example the temperature dependence of the gaps and of the critical fields and the effect of a magnetic field on the gap amplitudes. Then, we show how point-contact spectroscopy can provide useful information about the surface properties of MgB₂ thin films (e.g. T_c, gap amplitude(s), clean or dirty-limit conditions) in view of their optimization for the fabrication of tunnel and Josephson junctions for applications in superconducting electronics (AFM film). UNDER CONSTRUCTION

R.S. Gonnelli, D. Daghero, A. Calzolari, G.A. Ummarino, Valeria Dellarocca, V.A. Stepanov, S.M. Kazakov, J. Karpinski, Chiara Portesi, E. Monticone, Valeria Ferrando, C. Ferdeghini
“Point-contact spectroscopy in MgB₂: from fundamental Physics to Thin-Film Characterization”, submitted, (cond-mat/0309545).