Meissner Levitation of a Millimeter-Size Neodymium Magnet Within a Superconducting Radio Frequency Cavity
| Autor: | Raymond Y. Chiao, Jay E. Sharping, Jacob Pate, Jeffrey Boone Miller, Nabin K. Raut |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Materials science
business.industry Superconducting radio frequency Superconducting magnet Condensed Matter Physics 01 natural sciences Electronic Optical and Magnetic Materials Neodymium magnet Optics Physics::Plasma Physics Condensed Matter::Superconductivity Magnet 0103 physical sciences Levitation Physics::Accelerator Physics Electrical and Electronic Engineering Coaxial 010306 general physics business Critical field Magnetic levitation |
| Zdroj: | IEEE Transactions on Applied Superconductivity. 31:1-4 |
| ISSN: | 2378-7074 1051-8223 |
| DOI: | 10.1109/tasc.2021.3053206 |
| Popis: | We report on the magnetic levitation of a millimeter-sized neodymium permanent magnet within the interior of a superconducting radio frequency (SRF) cavity. To the best of our knowledge, this is the first experimental work on levitating a magnet within an SRF cavity. The cavity is a coaxial quarter-wave microwave resonator made from 6061 aluminum, having a resonance frequency of 10 GHz and a loaded Q of 1400. The cylindrical magnet (N50) has a height of 1 mm, a diameter of 0.75 mm, a mass of 4 mg, and a remanence of 1.44 T. This produces a peak magnetic field 140 times greater than the critical field of aluminum. The magnet is placed either on the top of the coaxial portion of the cavity or on the cavity floor before cooling it below the superconducting transition temperature of aluminum. The coaxial mode's resonance frequency shifts as a function of the levitation height of the magnet and gives an idea of the magnet's position and mechanical motion. We observe a transition at a temperature of 650 mK where the Meissner effect levitates the magnet as the material beneath the magnet becomes superconducting. The magnet is levitated to a height of 2.5 mm above the surface of the cavity stub, which is a sufficient separation for the field strength of the magnet at the surface of the stub to be less than the critical field strength of the superconducting aluminum. We measure a 120 MHz upshift in the cavity resonance as the magnet is levitated from the top of the stub and 15 MHz downshift as it levitates from the floor of the cavity. Our measurements are consistent over several heating and cooling cycles. Our work provides a path towards a novel optomechanical system. |
| Databáze: | OpenAIRE |
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