Raman opalescence near the phase transition point in lead germanate crystals

Effect of Nd+3 and K+ Substitutions on Phase Transition of Ferroelectric lead Germanate Single Crystals

Double doped (Nd + K) ferroelectric lead germanate single crystals were grown by controlled cooling of melt. Greenish tinge crystals of 5 x 4 x 3 mm were found embedded in the solid. Pure lead germanate was grown by cz technique for comparative analysis. Dielectric constant and loss tangent of pure crystals showed a sharp dielectric peak at 179°C while dielectric constant of doped crystals show...

Critical point for the blue-phase-III-isotropic phase transition in chiral liquid crystals.

Nonlinear photonic crystals near the supercollimation point.

We uncover a strong coupling between nonlinearity and diffraction in a photonic crystal at the supercollimation point. We show that this is modeled by a nonlinear diffraction term in a nonlinear-Schrödinger-type equation in which the properties of solitons are investigated. Linear stability analysis shows solitons are stable in an existence domain that obeys the Vakhitov-Kolokolov criterium. In...

Investigation into the temperature dependence of isotropic- nematic phase transition of Gay- Berne liquid crystals

Density functional approach was used to study the isotropic- nematic (I-N) transition and calculate the values of freezing parameters of the Gay- Berne liquid crystal model. New direct and pair correlation functions of a molecular fluid with Gay- Berne pair potential were used. These new functions were used in density functional theory as input to calculate the isotropic- nematic transition den...

Electric Field Induced Phase Transition in KDP Crystal Near Curie Point: Raman and X-ray Scattering Studies

X-ray scattering measurements are performed in order to verify that the mechanism leading to the DC electric field induced C 2v → C 6=19 2v phase transition in KDP crystal at 119 K is the changing of the local sites symmetries of phosphate group from C2 in the C 19 2v phase to Cs in the C 6=19 2v phase. It is shown by analyzing the integrated intensity of the (800) and (080) reflections that un...