The effect of magnet configurations on the levitation force of melt processed YBCO bulk superconductors

The high levitation force of YBCO bulk superconductors makes it possible for many applications such as magnetic bearings, flywheels and magnetic levitation transport systems etc. But for a given superconductor, the levitation forces are much different with different magnetic field distributions. In this paper, many small magnets (10 × 10 × 10 cm³) with the B = 0.5 T on the top surface have been selected to investigate the effects of the magnet numbers and the configurations of the same number of magnets on the levitation force of a single-domain YBCO bulk superconductor (30 mm in diameter). It is found that the levitation force increases with the increasing of the magnet numbers (such as the levitation force increases from 18.8 to 49 N with the increasing of the magnet numbers from 1 to 12) and saturated when the size of the composed magnet becomes larger than that of the YBCO bulk. It is also found that the levitation forces are different with different magnet configurations for a given YBCO bulk and the same number of the magnets, the smaller the magnetic poles in the composed magnets, the higher the levitation force of the YBCO bulks. The results will be discussed in detail.