Transmission electron microscopy and neutron powder diffraction studies of GdFeO3 type SrNbO3

Stoichiometric SrNbO3; with a GdFeO3 type structure was synthesized between 1300 and 1550 degrees C in Ar-filled and sealed niobium ampoules. Its crystal structure was refined using time-of-flight neutron diffraction data. Space group Pnma: a = root 2.a(p) = 5.6894(2) Angstrom; b = 2.a(p) = 8.0684(1) Angstrom; c = root 2.a(p) = 5.6944(2) Angstrom; R-F2 = 0.020; and R-p = 0.034. High-resolution electron microscopy and electron diffraction studies frequently revealed structural defects in SrNbO3. X-ray and electron diffraction studies showed cubic symmetry for SrNbO3 synthesized below 1300 degrees C and for compounds with nominal composition Sr0.8NbO3 synthesized between 1200 and 1550 degrees C. SrNbO3 was found to be temperature independently paramagnetic. (C) 1999 Academic Press.