Levitation force in YBCO/Nd-Fe-B permanent magnet system

This paper presents an experimental study of the levitation force on a bulk high-temperature superconducting YBCO disk in liquid nitrogen above a Nd-Fe-B permanent magnet disk. The force data agree with Kordynk's "frozen-image" model that states that levitation force is independent of YBCO disk thickness and is greater with defective YBCO disks than with defect-free YBCO disks.