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

Abstract

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.

Ferroelectricity and competing interactions in Ho-deficient non-stoichiometric orthorhombic HoMnO3

“…The extremely low-T independent Dy spin ordering does have this physics. 11,15 In this work, we provide the evidence with the competing Ho-Mn coupling and independent Ho spin interaction from the aspect of spin order induced ferroelectricity. It is nice to find out a roadmap to degrade the independent Ho spin interaction so that the Mn-spin order induced Ho spin ordering can be promoted.…”

“…The core ingredient is the competition between the Mn spin order induced Dy spin ordering and the independent Dy spin ordering in the low temperature (T) range. 11,15 It is understood that o-DyMnO 3 is a representative system accommodating both the antisymmetric Mn-Mn exchange striction induced ferroelectricity and the symmetric Dy-Mn exchange striction induced ferroelectricity, both of which are associated with the noncollinear Mn CS order and the induced Dy CS order. [13][14][15][16] Along this line, similar concern is raised for another representative system o-HoMnO 3 , which is believed to accommodate the symmetric Mn-Mn exchange striction induced ferroelectricity since the Mn spins favors the E-AFM order.…”