摘要
While the ferroelectricity in type-II multiferroic rare-earth manganites is believed to be generated by the inverse Dzyaloshinskii-Moriya （DM） interaction （spin orbit coupling） associated with the Mn spiral spin order, recent results revealed the strong spin-lattice coupling arising from the Dy-Mn spin interaction in DyMn03, which may also be an ingredient contributing to the ferroelectricity. In this work, we summarize our recent experiments on this issue by performing a series of rare-earth site nonmagnetic Y and magnetic Ho substitutions at Dy site for DyMn03. It is demonstrated that the Dy Mn spin interaction contributes to the ferroelectric polarization through the symmetric exchange striction mechanism （spin-lattice coupling）. A coexistence of the spin orbit coupling and spin-lattice coupling in one compound is confirmed. At the same time, the independent Dy antiferromagnetic spin order at low temperature can be effectively suppressed by the substitutions, beneficial to the polarization enhancement.
While the ferroelectricity in type-II multiferroic rare-earth manganites is believed to be generated by the inverse Dzyaloshinskii-Moriya （DM） interaction （spin orbit coupling） associated with the Mn spiral spin order, recent results revealed the strong spin-lattice coupling arising from the Dy-Mn spin interaction in DyMn03, which may also be an ingredient contributing to the ferroelectricity. In this work, we summarize our recent experiments on this issue by performing a series of rare-earth site nonmagnetic Y and magnetic Ho substitutions at Dy site for DyMn03. It is demonstrated that the Dy Mn spin interaction contributes to the ferroelectric polarization through the symmetric exchange striction mechanism （spin-lattice coupling）. A coexistence of the spin orbit coupling and spin-lattice coupling in one compound is confirmed. At the same time, the independent Dy antiferromagnetic spin order at low temperature can be effectively suppressed by the substitutions, beneficial to the polarization enhancement.
