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Large NdP 5 O 14 crystal with dimension of 15 × 25 × 60 mm 3 has been grown by flux method. The spontaneous strains and ferroelastic domain structures have been investigated by high resolution X-ray diffractometry for the first time. The reflection peak separations resulting from the misorientation between matrix domain and ferroelastic domain were observed in the rocking curves for several different reflections. Based on the features of the reflection peak separations, the ferroelastic domain structures were determined. It is found that most of the ferroelastic domains in NdP 5 O 14 are of type-a, while type-b ferroelastic domains only appear in the serious strain regions. Based on the domain structures of NdP 5 O 14 , the reflection peak separations for 802, 402 and 204 reflections were calculated respectively. And the experimental observations are in agreement with the calculations very well. In addition, the spontaneous strain in NdP 5 O 14 was determined to be 0.0082 by measuring the peak separation between two 800 diffraction from the matrix domain and the ferroelastic domain respectively. A detailed discussion on domain structures in the crystal is given in terms of structural and symmetric analyses. [ABSTRACT FROM AUTHOR]

Examines the characteristics of KTiOAsO4 (KTA) crystals from tungstate fluxes. Analysis of the anomalous scattering and ferroelectric domain of KTA; Mechanism of domain inversion via two-fold-axis in terms of the structural characteristics of KTA; Use of etching and multiple-crystal x-ray topography to investigate the domain-inverted grating of KTA.

Examines the contrast reversal of antiparallel domains in copper-doped crystals. Use of synchrotron topography; Presence of ferroelectric x-ray anomalous-scattering effect at the wavelength; Polarity of the domain walls; Formation of domain walls to compensate the charges from the inhomogeneous distributions of metal atoms in the bulk crystals.

High purity KTiOPO4 (KTP) crystals have been grown using a flux method. The quality, SHG efficiency and damage threshold of KTP crystals grown from high purity reagents were compared with those grown from commercial reagents. Experimental results indicate that KTP crystals using a high purity charge contain less impurities and possess higher SHG efficiency and damage threshold than do crystals grown from commercial reagents. It is proposed that decreasing the concentrations of impurities is an effective way of raising the damage threshold for KTP crystals. [Copyright &y& Elsevier]