Superparamagnetism and Blocking in Ferronematic Liquid Crystals

The addition of a few percent of the appropriate ferrofluid to a liquid crystal produces a ferronematic which can be oriented in low fields on the order of .01 T with the directors of the micelles becoming parallel to the field direction [1,2,3]. However the ferrofluid particles are paramagnetic at room temperature and should be incapable of orienting the ferronematic. It is the purpose of this communication to resolve this apparent paradox. (1)F. Brochard and P.G. de Gennes, J.Phys.(Paris) 31, 691 (1971). (2)A M Figueiredo Neto, and M M F Saba, Phys. Rev. A 34, 3483 (1986) (3)C.Y.Matuo, F A Tourinho, and A M Figueiredo Neto, J. Magn. Magn. Mater. 122, 53 (1993).