Melt-texturing of carbon containing YBa(sub 2)Cu(sub 3)O(sub 7-x): Influence of processing parameters on microstructure and flux-pinning behavior

摘要

A detailed study of the flux-pinning behavior of sintered and melt-textured YBa(sub 2)Cu(sub 3)O(sub 7-x) has been carried out by means of microstructural investigations (optical microscopy, SEM, TEM, EDS, DTA, and XRD) and magnetization measurements. It was found that both microstructure and magnetization behavior strongly depend on the starting material, the production method, and the maximum processing temperature. In our experiments, the critical current density, J(sub c), increased with increasing processing temperature between 920(degrees)C and 1050(degrees)C (25 - 130 emu/cm(sup 3)), but those samples processed at temperatures just above the peritectic transformation point (1020 OC and 1030 OC) exhibited a decreased J(sub c). The carbon content of the starting powder and the powder's melting behavior seem to play an important role in the development of microstructure and flux-pinning behavior during melt-texturing. A comparison of our data with previously published results shows that an optimized melt-texturing process can result in materials with critical current densities comparable to those of samples produced by Quench-Melt Growth.