Synthesis, Mo-valence state, thermal stability and thermoelectric properties of SrMoO3−xNx (x>1) oxynitride perovskites

✍ Scribed by D. Logvinovich; R. Aguiar; R. Robert; M. Trottmann; S.G. Ebbinghaus; A. Reller; A. Weidenkaff

• Book ID: 104029949
• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 461 KB
• Volume: 180
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2007.06.035

✦ Synopsis

Oxynitrides of the general composition SrMoO 3Àx N x (x41) were synthesized by thermal ammonolysis of crystalline SrMoO 4 . According to neutron and X-ray diffraction experiments, the materials crystallize in the cubic perovskite structure (space group Pm3 ¯m). X-ray absorption spectroscopy (XAS) shows evidence of local distortions of the Mo(O,N) 6 octahedra. The oxidation states of Mo determined by X-ray absorption near edge structure (XANES) spectroscopy are slightly lower than that calculated from the oxygen/ nitrogen(O/N) content. The disagreement arises from the higher covalence of the Mo-N bonding when compared to the Mo-O bonding (''chemical shift''). The electrical transport properties of the samples are strongly different from SrMoO 3 . It was found that the conductivity of the samples decreases with increasing nitrogen content. The Seebeck coefficient values are up to three times higher than those of SrMoO 3 .