1988 Fiscal Year Final Research Report Summary
Growth and Defect Generation in CuCl Single Crystals as a Light Modulator
| Project/Area Number |
62460225
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
結晶学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
INOUE Tetsuo IMR, Tohoku Univ. Assistant, 金属材料研究所, 助手 (60005923)
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| Co-Investigator(Kenkyū-buntansha) |
UWAHA Makio IMR, Tohoku Univ. Assistant, 金属材料研究所, 助手 (30183213)
KOMATSU Hiroshi IMR, Tohoku Univ. Professor, 金属材料研究所, 教授 (00108565)
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| Project Period (FY) |
1987 – 1988
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| Keywords | CuCl / Flux growth / TSSG method / 暗視野法 |
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| Research Abstract |
The raw CuCl was purified first by the wet chemical purification (recrystallization) and then by vacuum sublimation in order to improve the quality of the crystals grown. The CuCl crystals were grown from the solution containing KCl as a flux agent using the top seeded solution growth. The growth conditions investigated here were as follows ; (i) the orientations of the seed crystals : [100], [111] and [110], (ii) concentrations of the KCl flux : 3.0-24.9 mol.%, (iii) growth rates : 0.25-5.22 mm/h. The results were as follows.
1. The crystals were not grown in the same orientations as that of the seed in any cases. This is because the crystals grown were divided into several grains by the grain boundaries and/or twin boundaries.
2. As the concentration of KCl was decreased, the degree of transparency and grain size were increased.
3. If the growth rate was high (5.22 mm/h), the crystals were clouded even though the concentration of KCl was low (3.0 mol.% KCl).
4. The most suitable growth conditions for transparent and large crystals (5-10 mm in diameter) were at the KCl concentration of 3.0 mol.% and the growth rate of --0.6 mm/h.
5. The distribution of KCl inclusions in the crystals were examined using the dark-field illumination. The distribution patterns of the KCl inclusions varied from random to cellular and clouded patterns with the increase of the growth rates and the KCl flux concentrations. These results were explained on the basis of the constitutional supercooling.
6. The internal strain in the crystals were examined using the photo-elastic method. It was found that the internal strain could be considerably eliminated by annealing the crystals at 350゜ C for 24 h.
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