Commensurate Dy magnetic ordering associated with incommensurate lattice distortion in orthorhombic DyMnO3

TL;DR

This study reveals that in DyMnO3, Dy magnetic moments order in a commensurate pattern below 5K, inducing an incommensurate lattice distortion and affecting Mn magnetic and structural modulations, highlighting complex magnetic-structural interactions.

Contribution

It demonstrates the coexistence of commensurate Dy magnetic order with incommensurate lattice modulation and their interference with Mn-induced distortions in DyMnO3.

Findings

Dy magnetic moments order below 5K with a 0.5 b* propagation vector.

An incommensurate lattice modulation with 0.905 b* appears at low temperatures.

Mn and Dy magnetic and structural distortions strongly interfere in DyMnO3.

Abstract

Synchrotron x-ray diffraction and resonant magnetic scattering experiments on single crystal DyMnO3 have been carried out between 4 and 40 K. Below TN(Dy) = 5K, the Dy magnetic moments order in a commensurate structure with propagation vector 0.5 b*. Simultaneous with the Dy magnetic ordering, an incommensurate lattice modulation with propagation vector 0.905 b* evolves while the original Mn induced modulation is suppressed and shifts from 0.78 b* to 0.81 b*. This points to a strong interference of Mn and Dy induced structural distortions in DyMnO3 besides a magnetic coupling between the Mn and Dy magnetic moments.