Critical state of YBCO superconductors with artificially patterned holes

The magnetic behavior of melt-textured YBCO materials containing columnar holes has been systematically investigated with the help of a new "current-tracer" software based on the critical state model, and magnetic Hall probe imaging. The influence of the different geometrical distribution of holes, hole size and hole density on the remanent magnetization profiles and the effective-to-local critical current density ratio is discussed. For the single-crystalline YBCO samples with artificially patterned holes studied, the measured magnetization maps and J/sub c//sup eff//Jc ratios agree nicely with the simulations.