Coupled director and polarization fluctuations in suspensions of ferroelectric nanoparticles in nematic liquid crystals.
In colloidal suspensions of nanosized ferroelectric particles and nematic liquid crystals a large increase in the isotropic-nematic transition temperature has been observed recently. By dynamic light scattering we measured the relaxation rate of the nematic director fluctuations in colloidal systems with BaTiO3 and Sn2P2S6 particles. A substantial increase in the bend-mode relaxation rate, attributed to an increase in the bend elastic constant, is observed. A mode with relaxation rate around 200000 s(-1), independent of the scattering vector, is also observed. We propose that it represents the out-of-phase motion of the nematic director and average direction of the spontaneous polarization of the ferroelectric particles. No translation motion is observed, indicating that the particles may form chains.
Copic
Martin
M
J. Stefan Institute, Jamova 39, SI-1001 Ljubljana, Slovenia.
Mertelj
Alenka
A
Buchnev
Olexandr
O
Reznikov
Yuri
Y