Studies on the growth aspects of Bi2Sr2CaCu2O8+delta whiskers by vapour-liquid-solid mechanism

Growth aspects of superconducting Bi2Sr2CaCu2O8+delta (Bi-2212) whiskers by the vapour-liquid-solid (VLS) mechanism are reported. Formation of a Bi-ri ch liquid phase at the nucleation site is found to be the driving force for the growth by the VLS mechanism. The growth proceeds by the accumulation o f atomic species from the liquid and vapour phases and precipitation at the solid-liquid interface. The decrease in the degree of supersaturation of t he liquid phase leads to the compositional inhomogeneity in the grown whisk ers. A modified annealing process for the continuous supply of atomic speci es at the growth interface facilitates the growth of Bi-2212 whiskers of un iform composition. Whiskers grown by this mechanism are free from the inter -growth of either low T-c (2201) or high T-c (2223) phases. The resistivity measurements reveal a superconducting transition at 82 K. (C) 2001 Elsevie r Science B.V. All rights reserved.