Modern Approaches in Point-Contact Spectroscopy and Their Application to Probe Nanoclusters in Mesoscopic Materials

Modern approaches in point-contact spectroscopy were used for the identification of nanoclusters in mesoscopic materials. The conductive properties of a new layered mesoscopic superconductor SnNb5Se9 were studied. The investigation has been carried out with Ag(Cu)/SnNb5Se9 heterocontacts. Temperature dependence of heterocontact current-voltage characteristic derivatives gave the opportunity to study the superconducting behavior of the samples. Nanoclusters of the initial substances NbSe2 and Nb3Sn have been revealed. Their volume concentration is less than 10−7 in the host matrix. The value of the superconducting energy gap for SnNb5Se9 and its temperature dependence have been determined.