Electrical and magnetic properties of the two crystallographic forms of BaRuO3

We report the results of magnetic susceptibility and electrical resistivity measurements on single crystals of the nine-layer and four-layer crystallographic forms of BaRuO3. The two forms differ in the relative amounts of corner and face sharing of RuO6 octahedra. They display qualitatively different properties below approximately 100 K: the four-layer form shows a metallic resistivity down to low temperatures, while the nine-layer shows a crossover to a more resistive state. No local moment magnetism is observed in either phase below 400 K, which is of particular interest in the context of previously observed magnetic and superconducting phases in the Sr-Ru-O system. Resistive measurements to temperatures below 0.1 K reveal no occurrence of superconductivity in either form. [S0163-1829(99)09307-8].