Superconductivity in BaNbS₃ and BaNb₂S₅

BaNbS₃ and BaNb₂S₅ were synthesized using BaCO₃ and Nb₂O₅ in a nitrogen stream laden with CS₂. In some cases, samples were synthesized from the elements. BaNbS₃ has a hexagonal crystal structure characterized by quasi-one-dimensional Nb-Nb chains. The crystal structure of BaNb₂S₅ is hexagonal, but otherwise not fully characterized. We observed superconductivity at 0.89 K in BaNbS₃ and 0.95 K in BaNb₂S₅. Electrical resistivity, specific heat, magnetic susceptibility, and Hall effect were measured on the samples to determine their basic physical properties, including parameters that characterize the superconductiviy (e.g. energy gap and upper critical magnetic field). Our findings will be presented along with comparisons of the two compounds.