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Title: Permanent magnet with MgB{sub 2} bulk superconductor

Superconductors with persistent zero-resistance currents serve as permanent magnets for high-field applications requiring a strong and stable magnetic field, such as magnetic resonance imaging. The recent global helium shortage has quickened research into high-temperature superconductors (HTSs)—materials that can be used without conventional liquid-helium cooling to 4.2 K. Herein, we demonstrate that 40-K-class metallic HTS magnesium diboride (MgB{sub 2}) makes an excellent permanent bulk magnet, maintaining 3 T at 20 K for 1 week with an extremely high stability (<0.1 ppm/h). The magnetic field trapped in this magnet is uniformly distributed, as for single-crystalline neodymium-iron-boron. Magnetic hysteresis loop of the MgB{sub 2} permanent bulk magnet was determined. Because MgB{sub 2} is a simple-binary-line compound that does not contain rare-earth metals, polycrystalline bulk material can be industrially fabricated at low cost and with high yield to serve as strong magnets that are compatible with conventional compact cryocoolers, making MgB{sub 2} bulks promising for the next generation of Tesla-class permanent-magnet applications.
Authors:
 [1] ;  [2] ; ;  [3] ;  [1]
  1. The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan)
  2. (Japan)
  3. Railway Technical Research Institute, 2-8-38 Hikari, Kokubunji, Tokyo 185-8540 (Japan)
Publication Date:
OSTI Identifier:
22311152
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BORON COMPOUNDS; CURRENTS; HIGH-TC SUPERCONDUCTORS; HYSTERESIS; IRON COMPOUNDS; MAGNESIUM BORIDES; MAGNETIC FIELDS; MONOCRYSTALS; NEODYMIUM COMPOUNDS; NMR IMAGING; PERMANENT MAGNETS; POLYCRYSTALS; SHORTAGES; STABILITY; TEMPERATURE RANGE 0013-0065 K; TRAPPING