High concentration ferronematics in low magnetic fields

• Published in: Journal of magnetism and magnetic materials 2014-12, Vol.372, p.117-121
• Main Authors: Tóth-Katona, T., Salamon, P., Éber, N., Tomašovičová, N., Mitróová, Z., Kopčanský, P.
• Format: Article
• Language: English
• Subjects: Agglomeration; Boundaries; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Ferronematic; Liquid crystal; Liquid crystals; Magnetic fields; Magnetic liquids; Magnetic properties; Magnetic properties and materials; Magnetism; Nanoparticles; Nematic; Physics; Structural transition; Studies of specific magnetic materials
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2014.07.061

We investigated experimentally the magneto-optical and dielectric properties of magnetic-nanoparticle-doped nematic liquid crystals (ferronematics). Our studies focus on the effect of the very small orienting bias magnetic field Bbias, and that of the nematic director pretilt at the boundary surfaces in our systems sensitive to low magnetic fields. Based on the results we assert that Bbias is not necessarily required for a detectable response to low magnetic fields, and that the initial pretilt, as well as the aggregation of the nanoparticles play an important (though not yet explored enough) role. •Response to low magnetic fields was detected in high concentration ferronematics.•The role of the orienting bias magnetic field is discussed.•The influence of the pretilt angle and that of the aggregation is described.•Doping the liquid crystal with nanoparticles does not change the birefringence.•The phase transition temperature of the nematic does not change with doping.