Effects of Horizontal Cutting Depth on the Magnetic Properties of Single-Domain GdBCO Bulk Superconductors

The distribution of induced current in bulk superconductors plays a crucial role in determining their levitation force and trapped field. To investigate the impact of longitudinally-induced circulation on the magnetic properties of rare-earth barium–copper–oxide (REBCO) bulk superconductors, a single-domain gadolinium–barium–copper–oxide bulk, with a diameter of 30 mm and thickness of 10 mm, was cut horizontally at its semi-height, reaching depths of 0, 5, 10, 15, 20, 25, and 30 mm through a step-cutting method. The bulk’s levitation force and trapped field were analyzed in relation to the cutting depth. The results reveal a gradual decrease in both parameters with increasing cutting depth, which can be attributed to the obstruction of longitudinal circulation transmission caused by cutting. This phenomenon has been further elucidated by considering the magnetic characteristics of non-ideal type-II superconductors. Additionally, the local levitation force and trapped field measurements of the bulk further confirmed the conclusion obtained for the bulk considered as a whole. These findings contribute to a better understanding of the magnetic properties of REBCO bulk superconductors. Moreover, this study serves as a valuable reference for future research involving the cutting of bulks, offering significant insights into the practical design of bulk shape and properties through cutting methods.