Structural study of Yb1–xTbxMnO3manganites: site occupancy and coexistence of hexagonal and orthorhombic phases

Abstract

Polycrystalline samples of mixed Yb1−xTbxMnO3(x= 0, 0.25, 0.50, 0.75 and 1) were prepared by a solid state reaction procedure. Detailed crystal structure studies were performed using X-ray diffraction data obtained at room temperature. The application of the Rietveld method confirmed the reported hexagonalP63cmand orthorhombicPnmaphases forx= 0 (YbMnO3) andx= 1 (TbMnO3), respectively. A single hexagonal phase was also observed forx= 0.25, while in the case ofx= 0.50 andx= 0.75 both phases coexist in the produced samples. Crystallographic parameters for the pure compounds are in agreement with those found in the literature. Changes in the lattice parameters, unit-cell volume, polyhedral distortions and tilting observed in the mixed compounds are explained as a function ofx. Sharing of Tb3+and Yb3+ions between different sites is discussed.