Features of incommensurate phases in multiferroics

TL;DR

This paper provides a theoretical analysis of incommensurate phases in multiferroics, detailing their symmetry properties, the distribution of magnetization and polarization, and the effects of defects on phase transitions.

Contribution

It introduces a symmetry-based framework for understanding incommensurate phases and explores the impact of fractal defects on phase behavior in multiferroics.

Findings

Average magnetization and polarization in the incommensurate phase are zero.

Superspace symmetry groups contain all high-symmetry point groups.

Phase transition involves inversion loss within the incommensurate phase.

Abstract

We present the results of a theoretical analysis of two-dimensionally modulated incommensurate phases in crystals and define the space distribution of magnetization and polarization vector in the incommensurate phase and demonstrate that their averaging in the incommensurate phase period equals zero. We apply symmetry arguments and show that despite the fact that the phase transition in the system is described by reducible representation of the space group high symmetry phase the superspace symmetry group of the in-commensurate phase contains all symmetry point groups of the high symmetry phase. We analyze the influence of the fractal distribu-tion of defects on the evolution of the incommensurate phase and show that a phase transition occurs in the incommensurate phase that is accompanied by the inversion loss.