Solution landscapes of ferronematics in microfluidic channels

Abstract

We study solution landscapes for ferronematics, i.e., a dilute suspension of magnetic nanoparticles in a nematic liquid crystal host, in a one-dimensional (1D) channel geometry. Adopting the modelling framework in Bisht et al.(2020), the admissible ferronematic configurations are modelled in terms of critical points of an appropriately defined ferronematic energy. There are two types of critical points: full critical points that exploit all degrees of freedom and order reconstruction (OR) critical points. OR critical points have polydomain structures, with the polydomains separated by domain walls. We find that ferronematic systems are typically multistable, i.e., the free energy has multiple competing stable critical points, which model potentially physically observable configurations; the multistability is not a priori obvious. Further, we discover multiple stable and unstable OR solutions that differ in the locations and multiplicity of domain walls. The domain walls can act as binding sites in equilibrium processes and rafts for guided transport phenomena in non-equilibrium processes.