Manna, Kaustuv
Kaustuv Manna
Post-doctoral research scientist
Phone: +49 351 4646-3205

Topological Materials

Optical Floating Zone

The optical floating zone technique is used to grow the high quality single crystals of various metal oxides as well as intermetallic compounds. Using the light heating technique in this crucible free method enables us to grow the single crystals of both conducting as well as the non-conducting materials. This is a major advantage over the induction or electron beam heating, where only the conducting samples are possible to grow.

We employ model FZ-T-10000-H-HR-I-VPM-PC procured from Crystal Systems Inc., Japan. Here four ellipsoidal mirrors focus the light from halogen lamps onto a vertically held feed rod. A molten zone is formed and held between the seed and feed rods by its own surface tension. After stabilization, the molten zone is moved along the sample to grow single crystal. The growth rate can be up to: 300 mm/h and maximum temperature can be reached to 2200o C. The upper and lower shaft rotation can vary between 5-100 rpm, while total length of the grown crystal can be as long as 150 mm. The stability of the molten zone can be monitored by visualizing the growth through a CCD camera. The system is capable of growing crystals under different ambiance like O2, Ar and air with maximum pressure up to 9.5 bar. A magnetic liquid sealing helps to maintain the high-quality atmospheric state in high vacuum as well as high pressure condition continuously.

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