J. Phys. IV France 07 (1997) C1-565-C1-566
Study of Magnetic Fredericksz Transition in Ferronematics. Liquid Crystals Doped with Fine Magnetic ParticlesP. Kopcansky1, M. Koneracka1, V. Zavisova1, J. Jadzyn2, G. Czechowski2 and B. Zywucki2
1 Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 043 53 Kosice, Slovak Republic
2 Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 1 7, Poznan, Poland
The magnetic Fredericksz transition in ferronematics (thermotropic nematic liquid crystals 7CB and MBBA combined with fine magnetic particles of size 10 nm) as a function of concentration of magnetic particles was studied by using simple dielectric tneasurements. The increase of the threshold magnetic field is observed in 7CB based ferronematic while the decrease of threshold field in MBBA based ferronematic is observed when the concentration of magnetic particles is increased. Experimental results are disscussed in framework of Brochard, de Gennes and Burylov, Raikher theories.
© EDP Sciences 1997