Mechanism of growth of Bi2+xSr2-yCuO6+delta single crystals in gas cavities in a KC1 melt

摘要

High-quality Bi2+ xSr2-yCuO6+delta Single crystals in a wide range of superconducting properties, from optimally doped to strongly underdopcd (including, insulators), have been obtained by free growth in Vas cavities formed in a KCI flux. A model of crystal growth is proposed, in which the decisive parameter is the chemical transport in a cavity at a low partial oxygen pressure and feeding of the gaseous medium from the charge heated to a higher temperature. In this case, layer-by-layer growth through the vapor-solid mechanism is implemented. This growth, as the most ordered process, makes it possible to obtain faceted plates and whiskers with specular faces, without segregation of other phases.