Synthesis, crystal structure, stoichiometry and magnetic properties of (Ca1-xSrx)VO3

The alkaline-earth metal vanadium(IV) oxide system with formula (Ca1-x Sr-x )VO3 has been synthesized using the metallo-organic method. The oxides prep ared at temperatures of 1073-1173 K showed the presence of an oxygen excess while those obtained at higher temperatures (1273 K) where found to be sto ichiometric. The crystal structure of these oxides (stoichiometric and non- stoichiometric) is perovskite with different symmetry depending on the stro ntium substitution: orthorhombic (0 less than or equal to x less than or eq ual to 0.2), tetragonal (0.3 less than or equal to x less than or equal to 0.4), and cubic (0.75 less than or equal to x less than or equal to 1). The influence of strontium substitution on the [VO6] groups symmetry was also observed by vibrational spectroscopy. The electrical properties of the oxid es are not extensively influenced by the stoichiometry and cation substitut ion, (C) 1999 Elsevier Science Ltd.