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 prepared 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 stoichiometric. The crystal structure of these oxides (stoichiometric and non-stoichiometric) is perovskite with different symmetry depending on the strontium substitution: orthorhombic (0 less than or equal to x less than or equal 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 oxides are not extensively influenced by the stoichiometry and cation substitution, (C) 1999 Elsevier Science Ltd.