The magnetic order in multiferroic DyMnO3

Abstract With flexibility in tuning their electric and magnetic properties, multiferroics can be used in information exchange and storage in ways that are very different from the present electronic materials. Here we use resonant soft x-ray scattering spectroscopy to study the F -type ( 0 , τ , 0 ) and C -type (0, 1- 2 τ , 0) diffraction peaks from sinusoidal antiferromagnetic spin order in multiferroic DyMnO 3 . By comparing the temperature dependence of ordering wave vectors τ , peak intensities I , and correlation lengths λ measured at Mn L 2 -, O K -, and Dy M 5 -edges, we show that the nearly perfect locking between the ordering wave vectors from Dy 4 f states and Mn 3 d orbitals manifesting the second harmonic diffraction peak implies the notable orbital involvement in the coupling between Mn and Dy spins. Our DFT calculations further suggest that the lattice response to different antiferromagnetic ground states (A-type versus E-type) is much weaker in TbMnO 3 , in agreement with previous claim that the symmetric exchange interaction can be an important factor for understanding the ferroelectricity in DyMnO 3 than in TbMnO 3 .