• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.4
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• pp.165-171
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• 2009

In this study, ruby single crystals were successfully grown by flux method using an alumina crucible. The alumina crucible can be a substitute for the platinum crucible of high price. The ruby single crystals were grown in the temperature range of $915{\sim}1350^{\circ}C$ for 240 h, using $PbO-B_2O_3$ mixture. The grown ruby crystals with 9.02 ${\times}$ 6.36 mm in size exhibited red color and were transparent. The optical and structural properties were examined by UV-VIS spectrometry, FTIR and XRD. The optical properties of theses crystals were similar to those of the natural ruby and synthetic ruby grown by other methods.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.3
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• pp.250-260
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• 1995

In general, a sintered rod is used as a feed in the growth of crystals by the floating zone(FZ) method. The sintering condition of the feed rod affected the stability of molten zone because it influenced the interface shape between the feed and the melt during the crystal growth. In this study, rutile and ruby crystals were chosen as samples to analyze the effect of the microstructures of the feed rods. In sintering of the feed rod for the growth of rutile and ruby single crystals, the difference of grain size between the inner and the outer region of the feed rod increased with the sintering temperature and dwelling time. As a result, it altered melting behavior of the feed. The uniform grain size of the sintered rod was necessary for the optimum growing condition of crystals. The effect of pores in the feed rod was not a dominant factor to grow crystals by the FZ method, which was confirmed by growing crystals with nonsinterd rods as feeds.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.4
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• pp.521-527
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• 1997

Ruby single crystals of 6-7 mm in dialneter and 20-25 mm in length were grown by the xenon-arc type floating zone method using a self-designed FZHY1, Calcination and sintering conditions were investigated and optimum growth conditions were established for controlling the factors such as growth rates, rotation speeds and cooling rates. Also the available energy levels of $Cr^{3+}$ were calculated from transmission data. The growth direction of the crystals was [1010] direction identified by Laue back reflection pattern. The distribution of refractive indices on the wafer of the grown crystals was homogeneous except for the edges of the wafer. The crystals could be used as a laser material with a wavelength of 693 nm and a metastate level.