Calculation of magnetic levitation/suspension force of single grained Y-Ba-Cu-O superconductors

Top-seeded single-grained YBCO samples capable of levitating or suspending over kilograms of weight have been measured. However, the detailed relationship of the levitation or suspension forces between permanent magnets and single grained superconductor samples have not been fully studied, which is required to design a large scale system. In this report, an empirical method was used to calculate the levitation/suspension force. First, the magnetic field of the permanent magnet and the superconductor was measured by a Hall probe, which was mounted on a x-y stage. The corresponding circulating current, which results in the measured magnetic field distribution, could therefore be calculated. The force between these two sets of current distributions at various distances was calculated and compared with measured levitation/suspension forces. A good degree of agreement between the measured and calculated suspension/levitation force was achieved by this empirical method.