Translation domains in multiferroics

TL;DR

This paper explores translation domains in multiferroics, demonstrating how they can be observed and their significance in understanding the physical properties of these materials.

Contribution

It distinguishes between split-order-parameter and joint-order-parameter multiferroics, highlighting methods to resolve translation domains in each type.

Findings

Piezoresponse force microscopy reveals ferroelectric translation domains in YMnO₃.

Optical second harmonic generation observes magnetic translation domains in MnWO₄.

Translation domains significantly affect the symmetry and properties of multiferroics.

Abstract

Translation domains differing in the phase but not in the orientation of the corresponding order parameter are resolved in two types of multiferroics. Hexagonal (h-) YMnO$_3$ is a split-order-parameter multiferroic in which commensurate ferroelectric translation domains are resolved by piezoresponse force microscopy whereas MnWO$_4$ is a joint-order-parameter multiferroic in which incommensurate magnetic translation domains are observed by optical second harmonic generation. The pronounced manifestation of the generally rather "hidden" translation domains in these multiferroics and the associated drastic reduction of symmetry emphasize that the presence of translation domains must not be neglected when discussing the physical properties and functionalities of multiferroics.