ANÁLISIS ESTRUCTURAL EN MANGANITAS DEL TIPO R1-XSmXMnO3 (R: Y, Yb, Ho).

Yttrium and rare earth manganites crystallize in two principal phases: hexagonal and orthorhombic. For ions with small atomic radii Y, Yb and Ho the typical crystallization is hexagonal and for Sm, which has a smaller atomic radii, the crystallization is in orthorhombic phase. The preparation of the compounds R1-xSmxMnO3 was performed by the standard solid state reaction technique. Determination of crystal structure, lattice parameters and bond angle reported for these manganates were developed in the Rietveld method's context. The pure perovskites RMnO3 cristallized in the space group P63cm, the lattice parameters a and c achieve 6 Å and 11 Å, respectively, while SmMnO3 structure crystallizes at the special group Pnma. Rietveld refinement revealed the effects of Sm into the pure hexagonal structures, evidencing crystallographic changes with ortorrombic trends for strong concentrations of Sm. [ABSTRACT FROM AUTHOR]