Single crystals of new Ruddlesden-Popper phases (SrLa)3V2O7 and Sr4V3O9.7: Preparation, crystal structure, and electrical resistivity

Single crystals of Sr1.5La1.5V2O7 (Sr3Ti2O7-type) and Sr4V3O9.7 (Sr4Ti3O10-type) have been grown by a melt method in molybdenum crucibles at high temperatures and from a strontium borate flux. Crystal structures have been refined from single crystal X-ray data. The crystals are large enough for resistivity measurements: Sr4V3O9.7 is metallic down to 4.2 K, while Sr1.5La1.5V2O7 is a semiconductor. A possible correlation exists between the observed electrical properties and the degree of distortion in the VO polyhedra.