Investigation on the Spontaneous Strain and Ferroelastic Domain Structures in NdP 5 O 14 Crystals by High Resolution X-Ray Diffractometry.

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]