Temperature dependence of the critical magnetic field of the structural transition in MBBA-based ferronematics |
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| Authors: | N. Tomašovičová M. KONERACKÁ P. Kopčanský M. Timko V. Závišová |
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| Affiliation: | 1. Institute of Experimental Physics, Slovak Academy of Sciences , Watsonova 47, 040 01 Ko?ice, Slovakia;2. Institute of Experimental Physics, Slovak Academy of Sciences , Watsonova 47, 040 01 Ko?ice, Slovakia;3. Grenoble High Magnetic Field Laboratory, CNRS , F-38042 Grenoble, Cedex 9, France |
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| Abstract: | We studied the structural transitions in ferronematics based on the thermotropic nematic liquid crystal MBBA (4′ -methoxybenzylidene-4-n-butylaniline) having a nematic-to-isotropic transition temperature T N–I?=?48.0○C and in MBBA-based ferronematics doped with a magnetic suspension consisting of Fe3O4 particles (10?nm in diameter) coated with oleic acid as a surfactant. The ferronematic samples were prepared with different volume concentrations of magnetic particles φ?=,1× 10?4, 2× 10?4 and 5×10?4. The temperature dependences of the critical magnetic fields in a bias electric field under strong applied magnetic fields are presented. We calculated the surface density of anchoring energy W at the nematic–magnetic particle boundary. Scaling of the structural transition in the MBBA and MBBA-based ferronematics with the temperature of the nematic-to-isotropic transition was observed. |
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| Keywords: | Fine magnetic particles Liquid crystal Anchoring energy |
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