Crystal Structure Refinement and Stability of LaFexNi1-xO3 Solid Solutions

H. FALC¨®N; A. E. GOETA; G. PUNTE; R. E. CARBONIO

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 1997 vol. 133 p. 379 - 379

p style="TEXT-ALIGN: justify; MARGIN: 0cm 0cm 10pt" class="MsoNormal">The crystal structure refinement of LaFexNi1-xO3 (0¡Üx¡Ü1) solid solutions was determined and analyzed by means of Rietveld refinement from X-ray powder diffraction data. The solid solutions with 0¡Üx<0.5 are isostructural with LaNiO3 and crystallize in the rhombohedral system, space group R-3c, while those with composition 0.5<x¡Ü1 are isoestructural with LaFeO3 and crystallize in the orthorhombic system, space group Pnma. All of the solutions are single phase except that with the intermediate composition (x=0.5), where both phases are observed. The cell volume increases with the iron content. This can be ascribed to the larger ionic radius of Fe3+ (HS) compared to Ni3+ (LS). LaFe0.25Ni0.75O3 was found to be single phase when prepared at temperatures as high as 1000o C, indicating an increase in the stability of the perovskite ph