In situinvestigation of the microstructure of KGd(WO sub(4)) sub(2) crystal growth boundary layer by confocal laser Raman microscopy

The microstructure of the solution near the crystal-solution interface is important for understanding the crystal growth mechanism. The microstructure of KGd(WO sub(4)) sub(2) crystal growth boundary layer was studied in situby confocal laser Raman microscopy. The experimental results show that a fr...

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Bibliographic Details
Published in:CrystEngComm 2012-11, Vol.14 (24), p.8722-8726
Main Authors: Zhang, Deming, Wang, Di, Zhang, Ji, Zhang, Qingli, Wan, Songming, Sun, Dunlu, Sun, Yulong, Yin, Shaotang
Format: Article
Language:English
Subjects:
Boundary layer
Confocal
Crystal growth
Distortion
Lasers
Microscopy
Microstructure
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Summary:The microstructure of the solution near the crystal-solution interface is important for understanding the crystal growth mechanism. The microstructure of KGd(WO sub(4)) sub(2) crystal growth boundary layer was studied in situby confocal laser Raman microscopy. The experimental results show that a free WO sub(4) tetrahedron is the basic structural unit in KGd(WO sub(4)) sub(2)-K sub(2)W sub(2)O sub(7) high temperature solution, and distorted WO sub(6) octahedron, WOW and WOOW oxygen bridge bonds begin to appear and increase in concentration with the positions moving towards the crystal-solution interface. Meanwhile, a quasi-ordered boundary layer with the thickness of 50-70 mu m was found near the interface. A growth mechanism of structural evolution was proposed in the boundary layer, where free WO sub(4) tetrahedra are transformed into distorted WO sub(6) octahedral long chain structures by forming the WOW and WOOW oxygen bridge bonds. According to the growth mechanism, the KGd(WO sub(4)) sub(2) crystal growth behaviour can be understood very well.
ISSN:1466-8033
DOI:10.1039/c2ce26369f