R. Muralidharan

Growth of bis(thiourea) cadmium chloride single crystals — a potential NLO material of organometallic complex

Growth aspects of bis(thiourea) cadmium chloride (BTCC) single crystals has been investigated. The crystals were grown from aqueous solution by slow cooling technique. The effect of pH on the growth rate and morphology has been discussed. The results indicated that as the pH of the solution is decreased the growth rate along the a-direction, R[100] increased and at a pH below 1, the morphology of the crystals changes from hexagonal to rectangular. Single crystal X-ray diffraction studies confirm the structure. Fourier transform infrared analysis and single crystal X-ray diffraction analysis confirms the presence of sulfur to cadmium bonds in the complex.

Metastable zonewidth, induction period and interfacial energy of zinc tris(thiourea) sulfate

Metastable zonewidth and induction period measurements on ZTS and ZTSP crystals are presented. The effect of pH on the solubility, metastable zonewidth and induction period has been studied. The effect of substitution of phosphate on the nucleation parameters has been presented. The interfacial energy for pure and phosphate mixed ZTS solutions at 30°C has also been estimated. There is a significant variation in the induction period and interfacial energy due to decrease in solution pH and phosphate substitution.

Growth and characterization of L-lysine doped TGS and TGSP single crystals

Abstract Growth aspects of l -lysine doped TGS and TGSP single crystals from aqueous solution by a temperature reduction method have been investigated. The effect of dopant on morphology and crystal properties has been studied. Ferroelectric domain patterns have been observed on the b-cut plates of doped crystals. Powder X-ray diffraction analysis confirms the structure and change in lattice parameter values for the doped crystals. The presence of dopant in the crystal lattice has been qualitatively confirmed by FTIR analysis. The dielectric permittivity and spontaneous polarization values have been estimated and the Curie temperature is found to increase upon doping. Hardness measurements were carried out on the grown crystals.

Investigations on the electrical and mechanical properties of triglycine sulphate single crystals modified with some rare earth metal ions

Abstract Single crystals of triglycine sulphate (TGS) modified with La 3+ , Ce 3+ and Nd 3+ have been grown from aqueous solutions by low-temperature solution growth method. The effect of rare earth ion dopants (La, Ce and Nd) on the ferroelectric properties of TGS is reported. Dielectric constant and dielectric loss have been measured for different frequencies. Dielectric measurements revealed that the dielectric constant of Ce-doped TGS increases rapidly at the transition temperature. Piezoelectric d 33 coefficient has been measured for the rare earth ions modified TGS crystals. Among the three dopants, Nd-doped TGS possesses low dielectric constant and high pyroelectric coefficient suggesting that this can be a potential material for infrared detectors.

Thermal and electrical studies on solution grown barium thiourea chloride single crystals

Barium thiourea chloride (BTC) single crystals were grown by slow evaporation of aqueous solution containing barium chloride and thiourea in the equimolar ratio. Thermal analysis of the grown crystal was carried out by thermogravimetric analysis (TGA)/DTG and the thermal parameters such as enthalpy, entropy and the activation energy were calculated. The AC conductivity and impedance measurements were carried out using conventional two probe technique in the temperature range of 300–400 K and in the frequency range of 100 Hz to 5 MHz. The conductivity was found to be very low and slowly increasing with the frequency with a peak around 5 MHz. Real and imaginary parts of complex impedance were determined for the grown sample as a function of frequency. Good transparency and thermal stability suggest BTC single crystals can be used for optical applications.