Long-Term Quality Observation in Large-Scale Production of Top-Seeded Melt Growth YBCO Bulks

Single grain YBCO prepared by a top-seeded melt growth (TSMG) technique has a significant potential in applications such as contactless bearings or magnetic coupling systems. For large-scale applications sustainable quality of production is essential. In this work, we present a statistical evaluation of levitation force for YBCO samples produced over a long period of time (two years). The production was done using batch processing with batches up to 32 pieces of bulk. This study shows results for several hundreds of large YBCO single grains with total mass more than 50 kg. Besides the levitation force, the trapped magnetic field was measured for selected samples of individual batches. The correlation between the quality control methods (levitation force and trapped field) was done. Potential risks for sustainable production were also identified and they are discussed in this work.