A modified airtight two-crucible method for growth of Bi-2212 whiskers from glassy pellets
Authors: Badica, P; Togano, K; Kumakura, H
Source: Superconductor Science and Technology, Volume 17, Number 7, July 2004 , pp. 891-898(8)
Publisher: IOP Publishing
Abstract:Bi2Sr2CaCu2Ox whiskers have been grown by a modified airtight two-crucible method, employing radial and vertical thermal gradients resulting from the relative position of the crucibles. A heating profile with a constant heating rate applied from 842 to 846 °C allows formation of whiskers up to 2 cm in length for a certain level of Al impurity in the glass. A cation-rich atmosphere is found to be a key intrinsic parameter. Our data confirm the importance of the thermal gradients, but this parameter is a somewhat extrinsic one and from a practical point of view should be correlated to other intrinsic parameters that influence growth atmosphere (i.e. to total and partial pressures). As-grown whiskers have composition Bi:Sr:Ca:Cu = (2.9–3.5):2:(1.7–2.05):(2.4–3.0) (normalized to Sr2), zero-resistance critical temperature Tc (R = 0) = 76–98 K and maximum transport critical current density above Jc = 104 A cm-2 at 77 K in self-field.
Document Type: Research Article
Publication date: July 1, 2004