AP-P-5
The magnetic force field performance and its application on a desktop-type magnetic levitation device exploiting high-gradient superconducting bulk magnets
16:45-18:15 29/11/2023
*Keita Takahashi1, Yui Koizumi1, Haruki Okubo1, Masahito Watanabe1
1. Department of Physics, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima, Tokyo, 171-8588, Japan
Large, single-grain bulk superconductors such as (RE)BaCuO (RE: Y or rare earth elements) can trap magnetic fields inside its material due to the flux pinning effect exploiting quasi-permanently induced electric current. Thus, on behalf of conventional permanent magnets or electromagnets, such the so-called trapped field magnets can be utilized as a compact and high-field magnetic source which should improve the magnetic performance and the magnet versatility, realizing a newly designed magnetic device for practical applications based on its machine potential.
Authors newly suggest, a high gradient trapped field magnet (HG-TFM), that incorporates two or more bulk components such that the opposite magnetic pole face stacked with each of them, can generate a magnetic field gradient product up to -1930 T2/m upon the trapped field of 8.6 T at the centre [1]. This would realize a novel desktop-type magnetic levitation device which enables to levitate diamagnetic materials in air without any physical supports due to the diamagnetic levitation phenomena and its wider use on application. To date, however, the three-dimensional magnetic field variation of the HG-TFM has not been investigated experimentally in a quasi-microgravity space. Those performance should be considered by critical current characteristics of bulk superconductors as well as thermal behaviours during magnetizing operation.
In this study, we have successfully operated the magnetic levitation device in which bulk superconductors were magnetised by field-cooled magnetization with an applied field of 8.05 T at an initial temperature of 25 K. The magnetic field and the temperature were measured consistently in the entire operation including before and after magnetization. Based on experimental results of the magnetic field gradient product, the scope of possibility for diamagnetic levitation was investigated for which several diamagnetic material candidates, plastics, glass, and heavy metals, were assumed. The extensibility of magnetic levitation on its practical application will be discussed.
1. K Takahashi, H Fujishiro and M D Ainslie, Supercond. Sci. Technol., 35 054003, 2022.
