Nanoscale physics

Magnetic Field-Controlled Light Transmission in Ferronematic  Liquid Crystals

Korostil A.A1., Krupa M.M.1  

1Department of Physics of Meso- and Nanocrystalline Magnetic Structures, Institute of Magnetism NAS and MES  of Ukraine.  Vernadsky av., 36b, Kyiv, Ukraine. E-mail: amand@rambler.ru

Ferronematic liquid crystals (FNLQ) are characterized by combination of the orientation structural ordering of the anisotropic (nematic) molecules (characterized by a so-called nematic vector) with the magnetic ordering of magnetic nanoparticles, arched by interphase interaction with the nematic molecules. The strong effect of an external magnetic field on an orientation ordering molecular structure occurs indirectly via its interaction with magnetic nanoparticle moments. The impact of the magnetic field on the molecular orientation is orders of magnitude larger than the direct magnetic influence due to the molecular diamagnetism [1-2]. The magnetic field-induced change of the nematic director is accompanied by the corresponding change of the optical axis, and the effect of the polarization twisting and birefringence of linear polarized light transmitted through the FNLC (the so-called magneto-optical effect). The transmission of the linearly polarized light through the FNLC sandwiched by two crossed polarized is characterized by the strong dependence of the transmitted light intensity on the applied magnetic field, that may have important applications in displays and photonics. Investigation of the magneto-optic effect is based on the macroscopic FNLC model and the Jones matrix description of light transmission. 

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