Influence of growth ambience and doping on the structural properties of multiferroic DyMnO3

We report on the single crystal growth of 50% Sr and Y doped multiferroic DyMnO3 using optical floating zone technique. A comparison of the effect of growth ambience and of chemical substitution on the crystal structure of DyMnO3 is attempted. It is observed that DyMnO3 adopts Pm3m   cubic structure with 50% Sr doping whereas with 50% Y doping, the crystal structure is hexagonal P63cmP63cm. Orthorhombic Pnma structure is adopted by DyMnO3 when grown in air, whereas hexagonal P63cmP63cm structure is obtained when grown under the ambience of argon. The structural polymorphism is discussed in terms of difference in ionic sizes of Sr, Y and Dy, comparable Gibbs free energies and coordination schemes of surrounding oxygens for hexagonal and orthorhombic structures of DyMnO3.

► We study the effect of doping divalent, non-magnetic Sr and Y in multiferroic DyMnO3.
► Crystal structure changes to cubic Pm3m   with Sr doping.
► Hexagonal P63cmP63cm structure results with Y doping.
► Sr doped system is a spin glass.
► Y doped compound is a frustrated antiferromagnet.