Concept of Pinning Levitation without Shielding Currents of a Permanent Magnet on YBCO Tapes

The YBCO tape high-Tc superconductor has high critical current density and strong pinning force. A field-cooled YBCO tape is suspended under a permanent magnet, and a small permanent magnet is levitated on the YBCO tapes. The stable suspension and levitation with the YBCO tape are obtained not by shielding currents but by pinning of flxsoids. The numerical pinning model without shielding currents is explained in formulation with Maxwell stress. The experimental results are numerically evaluated by using the numerical pinning model. The pinning force is discussed from experimental suspension limits. Levitation phenomena are also discussed for several cases with different gap lengths and magnets. The pinning force related to the critical currents of the YBCO tape is discussed from the numerical evaluation of the experimental results. Concept of pinning levitation with YBCO tapes is explained to design rotational levitation system.