Crystallographic orientation mapping with an electron backscattered diffractiontechnique in (Bi, Pb)2Sr2Ca2Cu3O10 superconductortapes

Abstract

It is believed that grain boundaries act as weak linksin limiting the critical current density (Jc) of bulkhigh-Tc superconductors. The weak-link problem can be greatlyreduced by elimination or minimization of large-angle grainboundaries. It has been reported that the distribution of theJc in (Bi, Pb)2Sr2Ca2Cu3O10+x (Bi2223)superconductor tapes presents a parabolic relationship in thetransverse cross section of the tapes, with the lowest currentsoccurring at the centre of the tapes. It was proposed that theJc distribution is strongly dependent on the localcrystallographic orientation distribution of the Bi2223 oxides.However, the local three-dimensional crystallographicorientation distribution of Bi2223 crystals in(Bi, Pb)2Sr2Ca2Cu3O10+x superconductor tapeshas not yet been experimentally determined. In this work, theelectron backscattered diffraction technique was employed to mapthe crystallographic orientation distribution, determine themisorientation of grain boundaries and also map themisorientation distribution in Bi2223 superconductor tapes.Through crystallographic orientation mapping, the relationshipbetween the crystallographic orientation distribution, theboundary misorientation distribution and the fabricationparameters may be understood. This can be used to optimize thefabrication processes thus increasing the critical currentdensity in Bi2223 superconductor tapes.