Processing, Y2BaCuO5 distribution and critical current density in large grain Pt-doped YBCO

We report an investigation of the processing oflarge grain YBCO (2 cm diameter, 0.5 cm thickness) containing 0, 0.1, 0.2 and 0.5 wt.% platinum (Pt) using seeded peritectic solidification. This process was observed to be extremely sensitive to the melting temperature, peritectic solidification temperature and cooling rate of the sample during grain growth. Differential thermal analysis of the Pt-doped powders and careful temperature calibration of the furnace were performed to determine optimum values of the thermal process parameters for each composition. The critical current density (Jc) of each specimen was measured by vibrating sample magnetometery from which the sample containing 0.1 wt.% Pt was identified as the optimum composition for high Jc engineering applications. Finally, detailed image analysis of the sub-micron sized Y2BaCuO5 (Y-211) inclusion distribution in the undoped sample was performed on SEM micrographs taken parallel to the a-b and a/b/-c crystallographic planes and used to investigate the variation of area fraction and number density of Y-211 inclusions with distance from the seed along different crystallographic directions.