Dynamics of Multiferroic Domain Wall in Spin-Cycloidal Ferroelectric DyMnO$_{3}$

TL;DR

This study reveals that the giant magnetocapacitance in DyMnO3 is due to the high-speed motion of thick multiferroic domain walls driven by electric fields, highlighting their magnetic origin and distinct behavior from conventional ferroelectric walls.

Contribution

It demonstrates that multiferroic domain walls in DyMnO3 are thick, highly mobile, and their dynamics are responsible for giant magnetocapacitance, differing from traditional ferroelectric domain walls.

Findings

GMC in DyMnO3 is due to domain wall motion, not electromagnons.

Multiferroic domain walls exhibit extremely high relaxation rates (~10^7 s^-1).

Domain walls are thick, reflecting magnetic origin.

Abstract

We report the dielectric dispersion of the giant magnetocapacitance (GMC) in multiferroic DyMnO$_{3}$ over a wide frequency range. The GMC is found to be attributable not to the softened electromagnon but to the electric-field-driven motion of multiferroic domain wall (DW). In contrast to conventional ferroelectric DWs, the present multiferroic DW motion holds extremely high relaxation rate of $\sim$$10^{7}$ s$^{-1}$ even at low temperatures. This mobile nature as well as the model simulation suggests that the multiferroic DW is not atomically thin as in ferroelectrics but thick, reflecting its magnetic origin.