Critical parameters in superconductor single crystal wires of doped lead telluride

Influence of Tl content on superconducting characteristics of thin single crystal wires of semiconductor compound PbTe<Tl> in the temperature region 0.4 divide 4,2 K and magnetic field up to 1,2 T are investigated. Thallium average concentration variation was 0.001 divide 0.02 at %. Single crystal wires (with diameters d = 5 divide 100 mum) were obtained from solution melt by filling of quartz capillary with the following crystallization of material. It is revealed, that at low temperatures in singlecrystal wires of PbTe<Tl> transition in the superconducting state is observed. The temperature of transition correlates with impurity concentration (for singlecrystal wires of PbTe<Tl> at thallium concentration 2% T_c=2,1K). Significant peak-effect is observed in the magnetic field near H_C1 and H_C2. Mechanisms leading to superconducting transition and anomalous dependence of critical current vs magnetic field in the vicinity of the H_C1 and H_C2 are discussed. The interpretation of the obtained results is given based on model of an impurity with skipped valence and flux line lattice deformation.