Synthesis and Crystal Structure of (Sr1−xLa1+x)Zn1−xO3.5−x/2(0.01≤x

Abstract

(Sr1−xLa1+x)Zn1−xO3.5−x/2 (0.01≤x<0.03), was prepared at 1373 K in the SrO–La2O3–ZnO system. The X-ray and neutron powder diffraction peaks were indexed with a body-centered tetragonal unit cell (a=3.75 and c=13.57 Å for the sample x=0.01). Weak diffuse superstructure reflections having periods of ∼2×a and ∼2×c were observed in electron diffraction patterns. The basic statistical structure of the superstructure was refined by Rietveld analysis for X-ray and neutron powder diffraction patterns of the sample x=0.01 with a model related to an oxygen-deficient K2NiF4-type structure, space group I4/mmm, Z=2, Rwp=0.1317, Rp=0.1052, RI=0.0566, and RF=0.0371 for X-ray data and Rwp=0.0796, Rp=0.0615, RI=0.0395, and RF=0.0252 for neutron data. In a local structure model, the Zn atom is coordinated by four oxygen atoms. Sr and La atoms are in the eightfold coordination of oxygen atoms.