Enhancement of grain alignment in slightly doped Bi-2212 superconducting fibers processed by laser floating zone (LFZ) method

Resumen del póster presentado a la 7th Asian Conference on Applied Superconductivity and Cryogenics celebrado en Capadocia (Turquia) del 23 al 25 de octubre de 2013.
In order to see the effect of Fe doping on alignment degree of LFZ grown Bi-2212 superconducting fibers, Bi2Sr2Ca1Cu2−xFexO8+δ (x = 0, 0.01, 0.03, 0.05 and 0.1) nominal composition has been prepared. The fibers obtained through laser floating zone method with a growth rate of 30 mm/h. had a diameter of 1.5-2 mm and up to 15 cm in length. The substitution effect on grain size and alignment degree of the fibers has been investigated by means of SEM and pole diagram, respectively. It has been seen that when the substitution rate reached the highest level, average grain size decreased about one third of the unsubstituted structure. Pole figure diagrams have been clearly showed that increasing doping rate created more aligned grains having ab crystal planes parallel to the growth axis. The most probable reason of this improvement was considered to be increased viscosity of melt region with the effect of doped metallic Fe atoms.