Effect of induced shielding current transmission in longitudinal direction on levitation force of melt grown single-domain YBa₂Cu ₃O_7-x cylindrical superconductor

A novel layer deletion method is used to experimentally investigate the effect of induced shielding current transmission (ISCT) in the longitudinal direction on the levitation force of a single-domain YBa₂Cu ₃O_7-x (YBCO) cylindrical superconductor (φ30×7 mm). In the experiment the sample was gradually sliced into two equal sheets, at the middle height along a diameter with 5 mm every step. The experimental results show that the lévitation force is closely related with the ISCT in the longitudinal direction. Any layer deletion, even a small piece of layer deletion can reduce the levitation force of the sample. After the whole layer was deleted the levitation force can diminish about 50%. It is also found that the levitation force is directly proportional to the effective factor of surface area, which is equal to the top surface area divided by the total surface area parallel to the top surface of the sample. Copyright by Science in China Press 2004.