  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.
