An optical floating zone (OFZ) model is developed, validated, and applied to obtain initial results for crystal growth in a novel high-pressure, single-lamp furnace. Computation with a realistic irradiation profile for zone heating results in dramatically different growth behavior than predicted using idealized Gaussian heating, though the discontinuities of the realistic profile prove challenging from a computational perspective. System pressure significantly affects buoyant flows in the surrounding atmosphere. Both driving force and flow strength increase nonlinearly with pressure, with the Grashof number growing with the cube of pressure and the Reynolds number scaling with pressure to the 3/2 power. For pressures of 100 bar and greater, flows of the surrounding phase strongly cool the growth sample, leading to significantly shorter melt zones, more deflected melt-solid interfaces, and weaker flows in the melt zone. Such effects reduce the likelihood of achieving stable growth conditions under very high pressure in this OFZ system.
Bibliographical noteFunding Information:
We acknowledge assistance from the entire Goma team at the University of New Mexico, particularly Andrew Cochrane, for insight and helpful discussions. We thank Hanna Dabkowska (McGill University) and John Mitchell (Argonne National Laboratory) for initial advice and encouragement. SSD would like to thank Scientific Instruments Dresden GmbH (ScIDre) for support to attend the 3rd Workshop on the Floating Zone Technique, Oxford University, September 16–18, 2019.
- A1. Computer simulation
- A1. Convection
- A1. Fluid flows
- A1. Heat transfer
- A2. Floating zone technique
- B1. Oxides