Bonfigt, O.; Somnitz, H.; Westerholt, K.; Bach, H.:

Crystal growth, characterization and physical properties of bismuth strontium calcium copper oxide (Bi2Sr2CaCu2O8+x).

In: Journal of Crystal Growth (J.Cryst.Growth), Jg. 128 (1993) ; Nr. 1-4, S. 725-728
ISSN: 0022-0248
Zeitschriftenaufsatz / Fach: Chemie
To improve the crystal quality and size of the high Tc superconductor Bi2Sr2CaCu2O8+x, the process of solidification near the m.p. in air was studied. The crystal structure formed from the melt depends on the O stoichiometry. After quenching to room temp., nonsuperconducting crystals with a higher O deficiency solidify. During annealing they transform into the usual quasi-tetragonal superconducting structure. Single crystals were grown by a modified Bridgman-Stockbarger technique with a very slow lowering rate. After about 10 days, single crystals were obtained which then were annealed at a low O pressure. They showed a supermodulation along the b-axis in the Laue pattern. The analyses of the phys. properties reveal the good quality of the crystals.