日本金属学会誌

J. Japan Inst. Metals, Vol. 59, No. 10 (1995),
pp. 1047-1054

Effects of Melt Convection on YBa2Cu3O7-x Single Crystal Growth by Pulling Method

Yasuo Namikawa, Masahiro Egami and Yuh Shiohara

Superconductivity Research Laboratory, ISTEC, Tokyo

Abstract:

The melt convection phenomena in YBa2Cu3O7-x (YBCO) single crystal growth by the modified pulling method (Solute Rich Liquid-Crystal Pulling method; SRL-CP method) have been investigated by using a numerical calculation. The finite difference method was used to calculate the steady state of the axisymmetric 2-dimensional incompressible viscous fluid system. In order to clarify the property of the melt convection, the dimensional analysis was performed with changing various parameters for the calculation, such as the crystal rotation rate, the melt viscosity, etc. The intensity ratio of the forced to the natural convection in the melt could be expressed by Re1.5Dsc0.7/Gr, where Re, Gr and Dsc were the Renolds number, the Grashof number and the diameter ratio of the crystal to the crucible, respectively. And also, the dimensionless crystal growth interface temperature, \varTheta could be expressed by \varTheta=C Re0.028Pr0.041Gr0.019Dsc0.064, where Pr was the Prandtl number and C was a constant. These results agreed well with the experimental results, and indicated that in this system, the heat transport was mainly dominated by the forced convection.
On the basis of these calculated results, the YBCO single crystal which was 14.5mm{×}14.5mm{×}13mm could be grown along the c-axis by the pulling method.


(Received June 5, 1995)

Keywords:

yttrium barium copper oxide, superconductor, single crystal growth, pulling method, convection, numerical simulation, dimensional analysis


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