Ferromagnetic nematic suspensions with negative dielectric anisotropy: Competing effects of magnetic and electric fields

The successful development of ferromagnetic nematic liquid crystals (FNLCs) has opened up a new direction for research in liquid crystals, which has the potential for technological applications. Previous research has predominantly focused on FNLCs based on positive dielectric anisotropy liquid crystals. In this paper, we report the preparation and comprehensive characterization of an FNLC with low birefringence and negative dielectric anisotropy. The suspension was prepared by dispersing and stabilizing barium hexaferrite nanoplatelets in the nematic liquid crystal. The suspension exhibits superior magnetocapacitance and magnetoviscous effects compared with conventional isotropic ferrofluids. We show that electric and magnetic fields applied simultaneously perpendicular to the director have competing effects on the director's alignment and the nanoplatelets' magnetic moments. This ferromagnetic nematic suspension broadens the scope of fundamental studies and has the potential for applications in magnetoelectric and magneto-optic sensors.