Transmission electron microscopy and neutron powder diffraction studies ofGdFeO3 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 crys tal structure was refined using time-of-flight neutron diffraction data. Sp ace 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 diffra ction studies showed cubic symmetry for SrNbO3 synthesized below 1300 degre es C and for compounds with nominal composition Sr0.8NbO3 synthesized betwe en 1200 and 1550 degrees C. SrNbO3 was found to be temperature independentl y paramagnetic. (C) 1999 Academic Press.