Nanocomposite of superparamagnetic maghemite nanoparticles and ferroelectric liquid crystal

We prepared a novel type of hybrid nanocomposite by mixing maghemite nanoparticles and a chiral liquid crystalline compound. The hybrid system exhibits ferroelectric as well superparamagnetic properties. The impact of nanoparticles and the effect of an applied magnetic field on the ferroelectric liquid crystalline properties were established. The ferroelectric properties are conserved up to a concentration of 5.6% of maghemite. The magnetic behavior of the composites is typical for a system of superparamagnetic nanoparticles with inter-particle dipolar interactions and surface spin disorder.

Microphotograph of the smectic phase for two nanocomposites with magnetic nanoparticles. A fan-shaped texture observed below the Iso–SmA phase transition (left); homeotropic texture with birefringent bands (right). Both textures coexist in different parts of the cell.

¹Institute of Physics, ASCR, Na Slovance 2, Prague 8, 182 21, Czech Republic
²Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University Prague, Ke Karlovu 2, 12116 Prague 2, Czech Republic
³Laboratory of Dielectrics and Magnetics, Chemistry