Tailored Nematic and Magnetization Profiles on 2D Polygons

TL;DR

This paper investigates how the shape and size of 2D polygons influence the stable nematic and magnetization configurations in magnetic nanoparticle suspensions, revealing effects of coupling strength on multistability and defect structures.

Contribution

It introduces a numerical study of the interplay between polygon geometry, nemato-magnetic coupling, and multistability in 2D nanoparticle-nematic systems, highlighting the effects of coupling sign on defect states.

Findings

Stable states with domain walls and defects coexist.

Positive coupling suppresses multistability.

Negative coupling enhances multistability.

Abstract

We study dilute suspensions of magnetic nanoparticles in a nematic host, on two-dimensional (2D) polygons. These systems are described by a nematic order parameter and a spontaneous magnetization, in the absence of any external fields. We study the stable states in terms of stable critical points of an appropriately defined free energy, with a nemato-magnetic coupling energy. We numerically study the interplay between the shape of the regular polygon, the size of the polygon and the strength of the nemato-magnetic coupling for the multistability of this prototype system. Our notable results include (i) the co-existence of stable states with domain walls and stable interior and boundary defects, (ii) the suppression of multistability for positive nemato-magnetic coupling, and (iii) the enhancement of multistability for negative nemato-magnetic coupling.