Physical Properties of Low Dimensional Ternary Transition-Metal Sulfides

Transition-metal sulfides exhibit behaviors such as metal-insulator transitions, superconductivity, and magnetism. They provide an interesting class of compounds for comparison to transition-metal oxides. In this work, polycrystalline SrTa₂S₅ and BaTa₂S₅ samples were synthesized. Large (15 x 15 x 0.25 mm³) single crystals of BiNbS₃ were grown by chemical vapor deposition. SrTa₂S₅ and BaTa₂S₅ superconduct at T_c=2.14 K and 3.2 K, respectively. BiNbS₃ shows no signs of superconductivity above ~0.4 K. The magnetic properties, specific heat, electrical resistivity, structural analysis, and compositional analysis will be discussed. The influence of hydrostatic pressure on the electrical resistivity will be presented.