Features of the electrical resistivity as a function of temperature in GdxPb1−xMo6S8 (x = 0.5, 0.7, and 0.9) superconductors

For the first time, the temperature ρ(T) and magnetic field ρ(H) dependences of the electrical resistivity have been studied in compounds GdxPb1−xMo6S8 (x = 0.5, 0.7, 0.9), in the temperature range 2–300 K and magnetic fields up to 9 T. In the absence of a magnetic field, the compounds Gd0.9Pb0.1Mo6S8 and Gd0.7Pb0.3Mo6S8 exhibit features along ρ(T) (maximum and minimum for Gd0.9Pb0.1Mo6S8, and an inflection for Gd0.7Pb0.3Mo6S8), in some temperature ranges. The ρ(T) dependence of Gd0.5Pb0.5Mo6S8 is monotonic over the entire investigated temperature range. The presence of a small positive magnetoresistance (up to 2%) is established, which peaks at temperatures where there are features. It is shown that the dependence of the magnetization M(T) in the studied temperature range does not have features associated with long-range magnetic transformations. It is suggested that the features along the ρ(T) of Gd0.9Pb0.1Mo6S8 and Gd0.7Pb0.3Mo6S8 can be caused by band structure rearrangement, and the appearance of two charge carrier channels that are responsible for the semiconductor and metallic behavior of the temperature dependences of the electrical resistivity.