Effect of the oxygenation time and of the sample thickness on the levitation force of top seeding melt-processed YBCO

The effect of the oxygenation time on the levitation force of top-seeded me lt-textured YBCO domains has been investigated. The existence of an optimal annealing time, depending on the sample volume, has been brought to the fo re. Longer annealings lead to a definitive deterioration of samples. A stud y of the levitation force versus thickness has been performed. The force ha s shown a monotonic dependence below a critical thickness as a function of the experimental conditions. When the sample thickness exceeds this critica l value, the force has reached its maximal value and saturates.