Comparison of the levitation forces of melt-processed YBaCuO superconductors for different magnets

It is difficult to compare the levitation force of superconductors for different magnets. A new parameter, alpha, is proposed in this paper, which is defined as the ratio of a superconducting levitation force to the limitation force for a given magnet. Using this parameter, the comparison between different superconducting levitation forces in melt-processed YBaCuO superconductors (QMG) has been done, such as a levitation force of 269 kN/m(2) (= 2.74 kgf/cm(2)) for a superconductor 77.3 mm in diameter and a magnet of NdFeB 50 mm in diameter, and a levitation force of 260 kN/m(2) (= 2.65 kgf/cm(2)) for a superconductor 46.5 mm in diameter and a magnet of PrFeBCu 36 mm in diameter. The former is alpha = 0.67 and the latter is alpha = 0.81.