Published online by Cambridge University Press: 03 March 2011
We developed an x-ray microdiffractometer using synchrotron radiation with which we analyzed microcrystal structures of heterogeneities in Tl-1223 superconducting wires prepared by different processes, i.e., partial melt and solid/liquid phase reaction. Samples with the nominal composition (Tl0.5Pb0.5)1(Sr0.8Ba0.2)2Ca2Cu3O9 were irradiated by focused SR x-rays of 6 μm × 8 μm size. The diffracted x-rays were two-dimensionally detected with an imaging plate. From crystal structure analysis, we identified the heterogeneities as BaPbO3 and (CaSr)2Cu1O3 which are present in Tl-1223 superconducting wires prepared by both processes. This suggested that these heterogeneous phases coexist with the stable phase in the Tl-1223 phase diagram. Consequently, it is necessary to develop a new processing method such as low temperature annealing or a suitable O2 pressure control method.