Growth of Large Rutile Single Crystal by Heater-Inserted Floating Zone Method

金红石单晶因其作为偏振器的应用而备受关注。采用浮动区(FZ)法成功地生长出大尺寸单晶，但由于熔融区仅靠熔体的表面张力来保持，难以生长出大尺寸的单晶。在本研究中，我们用加热器插入浮动区(加热器插入FZ)的方法生长了大尺寸的金红石单晶。在这种方法中，熔体支撑在Ir坩埚的底部，生长的晶体在坩埚中心有一个直径为2 mm的小孔，以保持熔体向生长区的连续进料。采用多孔氧化锆基隔热材料对金红石进行熔融是有效的。坩埚下方的隔热板对浅层温度梯度也是有效的，利用颗粒状的TiO2N连续进料可以长时间生长，用加热炉插入式FZ法成功地生长了直径约25 mm的金红石型单晶。用较大的坩埚可以生长出直径较大的金红石型单晶。

Rutile single crystals have attracted much attention for their applications as polarizar. The single crystal have success fully grown by the floating zone (FZ) method, which is difficult to grow large size crystals because the molten zone is kept only by surface tension of the melt. In this study, we have grown large rutile single crystals by the heater-inserted floating zone (heater-inserted FZ) method, in which the melts were supported at the bottom of the iridium crucible and growing crystals The size of a hole at the crucible center should be 2mm in diameter to keep continuous feeding of the melt to the growth region. The use of heat insulating materials made of porous zirconia was effective to melt the rutile. A heat-shielding plate below the crucible was also effective to shallow temperature gradient.Continuous feeding of raw materials were possible to grow for long time by using granular TiO_n. Rutile single crystals with about 25mm in diameter were successfully grown by the heater-inserted FZ method. It will be possible to grow rutile single crystals having larger diameters by a larger crucible.