Incompatible Magnetic Order in Multiferroic Hexagonal DyMnO3

TL;DR

This paper reveals that in multiferroic hexagonal DyMnO3, the magnetic orders of manganese and rare-earth lattices are incompatible, indicating weaker 3d-4f coupling than previously thought, which affects magnetoelectric coupling interpretations.

Contribution

It demonstrates the incompatible magnetic order of Mn and rare-earth lattices in h-DyMnO3, challenging assumptions about strong 3d-4f coupling in these materials.

Findings

Magnetic order of Mn and R lattices are incompatible in h-DyMnO3.

The 3d-4f coupling in h-RMnO3 is weaker than expected.

Magnetoelectric effects need re-evaluation regarding their origin.

Abstract

Magnetic order of the manganese and rare-earth lattices according to different symmetry representations is observed in multiferroic hexagonal (h-) DyMnO$_3$ by optical second harmonic generation and neutron diffraction. The incompatibility reveals that the 3d-4f coupling in the h-$R$MnO$_3$ system ($R$ = Sc, Y, In, Dy - Lu) is substantially less developed than commonly expected. As a consequence, magnetoelectric coupling effects in this type of split-order parameter multiferroic that were previously assigned to a pronounced 3d-4f coupling have now to be scrutinized with respect to their origin.