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Abstract: Growth of trivalent ions (La3+ and Nd3+) doped Bi4Ti3O12 (BIT) single crystal by self-flux method using excess Bi2O3 as flux is reported. The effects of trivalent ions on the structural, thermal, optical and ferroelectric properties of BIT crystal were investigated. The results of X-ray diffraction and thermal analysis, respectively, indicate that the lattice distortion, liquidus/crystallization temperatures of BIT considerably increase with La and Nd concentrations. Substitution of La in Bi3+ shifts the lower absorption edge towards the ultra-violet region (∼20–25nm), while no shift is observed for the BIT:Nd crystal. Regardless of the dopants, the optical microscopy patterns of the crystal surfaces reveal the existence of 90° domains. Dielectric measurements indicate that BIT:Nd crystals exhibit no significant variation in Curie temperature (T C) of BIT. Substitution of La and Nd in BIT increase both the remnant polarization (P r) and coercive field (E c) of BIT crystals. [Copyright &y& Elsevier]

Abstract: In this paper we report the growth of pure and Rhodium ion incorporated KTiOPO4 (Rh:KTP) single crystals by top seeded solution growth (TSSG) technique with an improved seeding procedure. The optical transmission/absorption spectra of pure and Rh:KTP crystals in the UV–VIS region are discussed. It is shown that the presence of Rh ion increases the indirect energy gap (E g) and shifts the lower absorption edge of KTP towards higher energy region. The ionic conductivity and dielectric properties of pure and Rh:KTP crystals were studied by means of impedance spectroscopy. The frequency and temperature dispersion behavior of dielectric constant and ionic conductivity of doped crystals are similar to pure KTP. Measured activation energies (E a) from the ionic conductivity and dielectric loss spectra indicate the existence of superionic conduction behavior. Linear thermal expansion coefficients of pure and doped crystals along the polar axis were obtained using a thermo mechanical analyzer. [Copyright &y& Elsevier]

KTiOPO4 single crystals doped with trivalent impurity ions of chromium were grown by spontaneous nucleation and seeded growth techniques. Structural refinement performed on the grown crystals by single crystal X-ray diffraction technique reveals that chromium ions occupy both the potassium sites with different filling coefficients. Incorporation of Cr3+ causes the absorption edge in the UV spectrum to shift towards the lower energy. The dependence of optical absorption coefficient with the incident photon energy in the UV–VIS region has been discussed. Optical and SEM studies indicate the existence of two-dimensional nucleation mechanisms. [Copyright &y& Elsevier]

Abstract: KNbO3 crystal is an incongruent melting crystal from a peritectic system. At first, a crystal was formed from the molten zone center of the stoichiometric composition using our original modified floating zone technique. Then the crystal was grown continuously using the firstly formed crystal as seed crystal. A small crystal with facets could be grown. The phase of the grown crystal was investigated in comparison to the phase grown by the conventional floating zone technique. [Copyright &y& Elsevier]

Abstract: Potassium niobate crystals were grown from high temperature solutions using the floating zone pulling-down technique. The starting solution compositions of K and Nb were changed from K:Nb=50:50 to 58:42. The lattice parameter, lattice volume and phase transformation temperature depended on the starting solution compositions. The solid solution region near the KNbO3 crystals was estimated to be expanding to a K-rich composition. [Copyright &y& Elsevier]