The Anchoring Energy of Liquid Crystal Molecules to Magnetic Particles in HAB-Based Ferronematics
N. Tomašovičová, M. Koneracká, P. Kopčanský, M. Timko, V. Závišová
Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Košice, Slovakia
A. Vajda, K. Fodor-Csorba, N. 'Eber, T. Tóth-Katona
Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O. Box 49, 1525 Budapest, Hungary
and J. Jadzyn
Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland
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Received: 9 07 2007;
In this work we describe the magnetic Freedericksz transition in HAB-based (4, 4'-di-n-heptylazoxybenzene) ferronematics. The ferronematic samples were prepared with two different volume concentrations of magnetic particles φ1 = 2×10-5 and φ2 = 2×10-4. The liquid crystal HAB is nematic at the temperatures from ≈53 °C to 70 °C and smectic A at the temperatures under 53 °C. The anisotropy of dielectric permitivity of HAB liquid crystal is positive in nematic phase and negative in smectic A phase. The magnetic Fredericksz transition was studied in nematic phase at temperature 60 °C.
DOI: 10.12693/APhysPolA.113.591
PACS numbers: 75.50.Mm, 61.30.Gd, 61.30.Hn