Abstract
The traveling solvent floating zone method was employed within an infrared radiation furnace to grow crystals of Bi 2 (Sr x Ca 3-x )Cu 2 O y , x=1.5-2. Crystals of various Sr/Ca ratios were obtained with lowest value approximately 1.32. The ratio of the temperature gradient G over the growth rate R, i.e. G/R, directly relates to the occurrence of constitutional supercooling. The minimum critical value of G/R in a stable growth condition is 4.5×10 11 Ks/m 2 from this experimental result and fundamental estimation. A rotation rate of 30rpm produced a slightly convex growth front and therefore enhanced the morphological stability of the growing crystal. Compositional analysis of the steady-state solvent zone indicated a primary crystallization field (PCF) located at the bismuth-rich and copper-deficient region relative to the 2212 stoichiometry, and this compositional range equaled proximal to Bi 2.425 Sr 1.911 Ca 0.807 Cu 1.857 O y . Meanwhile this PCF composed a corresponding tie-line relationship with a slightly copper-deficient 2212 single-phase region. © 2004 Elsevier B.V. All rights reserved.