Tunable structures of mixtures of magnetic particles in liquid-crystalline matrices

TL;DR

This study uses Monte Carlo simulations to explore how mixtures of magnetic particles and liquid crystals self-organize, revealing various ordered phases and the effects of magnetic fields on their alignment.

Contribution

It introduces a detailed simulation model for magnetic particle-liquid crystal mixtures, showing how magnetic interactions influence phase behavior and alignment.

Findings

Magnetic mixtures form ferromagnetic chains within liquid crystalline matrices.

The relative size of particles determines the chain orientation and resulting phases.

External magnetic fields can induce uniaxial or biaxial order in isotropic states.

Abstract

We investigate the self-organization of a binary mixture of similar sized rods and dipolar soft spheres by means of Monte-Carlo simulations. We model the interparticle interactions by employing anisotropic Gay-Berne, dipolar and soft-sphere interactions. In the limit of vanishing magnetic moments we obtain a variety of fully miscible liquid crystalline phases including nematic, smectic and lamellar phases. For the magnetic mixture, we find that the liquid crystalline matrix supports the formation of orientationally ordered ferromagnetic chains. Depending on the relative size of the species the chains align parallel or perpendicular to the director of the rods forming uniaxial or biaxial nematic, smectic and lamellar phases. As an exemplary external perturbation we apply a homogeneous magnetic field causing uniaxial or biaxial ordering to an otherwise isotropic state.