Grain size effect on GdFeO3-type lattice distortion and ferroelectric behavior in DyMnO3

The GdFeO3-type lattice distortion and consequent ferroelectric behavior in polycrystalline DyMnO3 with different grain sizes are studied by means of the Rietveld refinement of the X-ray diffraction at room temperature and ferroelectric measurements at low temperature. As evidenced by the variation in the in-plane MnOMn bond angle and the ferroelectric polarization, the distorted crystal structure and ferroelectric behavior of DyMnO3 can be effectively modulated by varying grain size. This work sheds light on the size effect in type-II multiferroic manganites.