CRYSTAL-STRUCTURE AND PHYSICAL-PROPERTIES OF A NEW LAYERED PEROVSKITE COMPOUND SR4V3O9.60

A new compound Sr4V3O9.60+/-0.01 has been synthesized by solid state reaction in flowing hydrogen atmosphere. Rietveld analysis based on X-ray diffraction data shows that it has a tetragonal structure (14/mmm) with a = 3.8457(1) angstrom and c = 27.9017(3) angstrom. The resistivity of the compound is 1.4 m-OMEGA.cm at room temperature (300 K) and decreases with decreasing temperature down to about 100 K followed by a slight increase with a further decrease of temperature. The magnetic susceptibility can be represented by a summation of temperature-independent and Curie-Weiss terms. The effective number of Bohr magnetons per vanadium atom is 0.37, which is considerably smaller than the free-ion values of 2.83 for V3+ and 1.73 for V4+. These results suggest that electron-electron interactions among the narrow pi* band (t2g symmetry) electrons are important in this compound.