Stability of multiferroicity against Dy/Mn off-stoichiometry in DyMnO3

We investigate the effects of slight Dy/Mn off-stoichiometry on the multiferroic behaviors of DyMnO3 (Dy1-xMn1+xO3). It is revealed that the distorted lattice structure and ferroelectric property exhibit higher stability against the Mn deficiency than the Dy deficiency. Since the electric polarization includes the contributions from the Mn-Mn and Dy-Mn interactions, the measured polarization exhibits different dependence on the Mn deficiency from that on the Dy deficiency. The present work suggests that the Dy/Mn off-stoichiometry is detrimental to the ferroelectricity, owing to the modulated spin interactions and reshuffled spin frustration. (C) 2014 AIP Publishing LLC.