Macrosegregation of Y2BaCuO5 particles in top-seeded melt textured monoliths

Y2BaCuO5 (Y-211) particles distributed in the textured matrix play an impor tant role for the superconducting properties. The Top-Seeded Melt Growth (T SMG) process always leads to a macrosegregation of Y-211. For TSMG and Mult i-Seeded Melt Growth (MSMG) monoliths, the characterization of the distribu tion of the Y-211 particles was performed over slices in the (001) plane an d (001) direction, respectively. As soon as the growth commences, a zone wi th a low content of less than 10 mol% of Y-211 appears. The low content of Y-211 can mainly be explained by the pushing/trapping model. This model rel ates the radii of the smallest trapped Y-211 particles to the growth rate. Furthermore, when the undercooling Delta T reaches 25 degrees C, the growth front stops to push the particles and starts to trap them. (C) 1999 Elsevi er Science B.V. All rights reserved.