Structural modifications of disordered YMn_(1-x)In_xO_3 solid solutions evidenced by infrared and Raman spectroscopies

摘要

Polycrystalline YMn_(1-x)In_xO_3 compounds were obtained by solid state reaction and found to present a blue color for high substitution rate. X-ray diffraction analyses reveal the formation of solid solutions and the increase of cell parameters following Vegard's law. Far infrared reflectivity and Raman scattering spectra show the presence of random disorder and structural modifications without phase transition. A detailed analysis of some phonon modes allows to explain the structural changes upon doping. It was found that monocaping YO_7 antiprisms are almost unaffected by substitution. However, results reveal the existence of two different MO_5 (M = In, Mn) trigonal bipyramids. Their apical Mn-O distances are shorter than In-O bonds and both distances increase with the substitution rate, which is consistent with the evolution of the cell parameters.