Levitation force of a YBaCuO bulk high temperature superconductor over a NdFeB guideway

One of the prospective applications of YBaCuO bulk high temperature superconductors (HTS) is for superconducting magnetic levitation (Maglev) vehicles. The levitation force of a single permanent magnet over a single superconducting YBaCuO bulk has been researched, but this is not enough for practical Maglev vehicles. In this paper, properties of the levitation force of a YBaCuO bulk HTS over a NdFeB guideway are investigated. The magnetic field at the guideway surface is up to 1.2 T. During the experiment, bulk YBaCuO is placed in a columnar liquid nitrogen vessel, whose bottom thickness is only 3.5 mm, and it is over the guideway. The YBaCuO is cooled in a zero magnetic field with liquid nitrogen and can move up and down at different velocities. The measurement process is fully controlled by a computer. In this case, there is a 103.4 N levitation force at a 5 mm gap between the YBaCuO (diameter=30 mm, thickness=14 mm) sample and the NdFeB guideway. In addition, the authors compare the levitation force over the NdFeB guideway with that over a single cylindrical NdFeB permanent magnet