Growth of high T{sub c} superconducting fibers using a miniaturized laser-heated float zone process. Annual progress report, January 1, 1992--December 31, 1992

This report covers the research done on {open_quotes}Growth of High Tc Superconducting Fibers using a Miniaturized Laser-Heated Float Zone Process{close_quotes} during the 12 months from Jan. 1, 1992 until Dec. 31, 1992. The major part of the work focused on phase relations and kinetics in the Bi{sub 2}O{sub 3}-SrO-CaO-CuO (BSCCO) system. By analyzing the crystal and melt composition, and the growth temperature of the float-zone samples, new data was obtained on the phase relationships. These results were shown to form a subset of solid solubility ranges reported by other investigators and was typical of the data available from other flux growth experiments. These experiments resulted in the development of a technique for the growth of long, single-phase 2212 samples. This was highly depended on starting material composition with Bi{sub 2.1}Sr{sub 1.8}Ca{sub 1.1}Cu{sub 2}O{sub y} being the most successful. Examination of the single phase 2212 growth interfaces was used to characterize the crystal/melt equilibrium conditions. These studies showed that 2212 crystal solidify from Bi{sub 2}O{sub 3}-rich and SrO-poor melts. Increasing melt concentrations of bismuth and cooper oxide increased the growth temperature. The sum of the bismuth and copper oxide in the crystals was invariant leading to the conclusion that the segregation of bismuth and copper oxide is interdependent. Work also proceeded on the new LHPG growth station