Application of elevated magnetic fields during growth of BiSrCaCuO superconducting whiskers and studies of growth defects for better understanding of the growth mechanism

Superconducting whiskers of Bi-2212 have been grown by an airtight crucible method in elevated magnetic fields, up to 10 T. Growth behavior with and without application of a magnetic field, as well as the SEM detailed study of the growth defects of the whiskers allow to emphasize some aspects of the growth mechanism. The conclusion is that whiskers are growing mainly through continuous crystallization at the base-end and from the so-called 'micro-crucible' formed by the glassy or powdered substrates. The supply of cations by a vapor transfer is very probable, but is taking place to the micro-crucible reaction site rather than to the droplet, as in the classic vapor-liquid-solid (VLS) growth mechanism. Therefore, whiskers grow by a modified VLS-microcrucible mechanism (MVLS-MC). Application of magnetic fields during growth has proven to be a powerful tool to investigate and influence some processes. Observation of stoichiometric Bi(Pb)-2212, CuO and Ca2CuO3 whiskers is also reported. (C) 2004 Elsevier B.V. All rights reserved.