Emergence of Biaxiality in Nematic Liquid Crystals with Magnetic Inclusions: Some Theoretical Insights

TL;DR

This paper presents a theoretical framework for understanding and controlling biaxiality in nematic liquid crystals with magnetic nanoparticles, explaining recent experimental observations and enabling manipulation of biaxial morphologies.

Contribution

It introduces a coarse-grained Ginzburg-Landau model to analyze biaxiality emergence in nematic liquid crystals with magnetic inclusions, providing quantitative insights.

Findings

Biaxial order can be induced by magnetic inclusions.

The model predicts controllable biaxial morphologies.

Quantitative estimates of biaxiality are achieved.

Abstract

The biaxial phase in nematic liquid crystals has been elusive for several decades after its prediction in the 1970s. A recent experimental breakthrough was achieved by Liu et al. [PNAS 113, 10479 (2016)] in a liquid crystalline medium with magnetic nanoparticles (MNPs). They exploited the different length scales of dipolar and magneto-nematic interactions to obtain an equilibrium state where the magnetic moments are at an angle to the nematic director. This tilt introduces a second distinguished direction for orientational ordering or biaxiality in the two-component system. Using coarse-grained Ginzburg-Landau free energy models for the nematic and magnetic fields, we provide a theoretical framework which allows for the manipulation of morphologies and quantitative estimates of biaxial order.