Langbahn Team – Weltmeisterschaft

Rare-earth barium copper oxide

Unit cell of YBCO

Rare-earth barium copper oxide (ReBCO[1]) is a family of chemical compounds known for exhibiting high-temperature superconductivity (HTS).[2] ReBCO superconductors have the potential to sustain stronger magnetic fields than other superconductor materials. Due to their high critical temperature and critical magnetic field, this class of materials are proposed for use in technical applications where conventional low-temperature superconductors do not suffice. This includes magnetic confinement fusion reactors such as the ARC reactor, allowing a more compact and potentially more economical construction,[3] and superconducting magnets to use in future particle accelerators to come after the Large Hadron Collider, which utilizes low-temperature superconductors.[4][5]

Materials

Any rare-earth element can be used in a ReBCO; popular choices include yttrium (YBCO), lanthanum (LBCO), samarium (Sm123),[6] neodymium (Nd123 and Nd422),[7] gadolinium (Gd123) and europium (Eu123),[8] where the numbers among parenthesis indicate the molar ratio among rare-earth, barium and copper.

YBCO

YBCO critical current (KA/cm2) vs absolute temperature (K), at different magnetic field (T).[9]

The most famous ReBCO is yttrium barium copper oxide, YBa2Cu3O7−x (or Y123), the first superconductor found with a critical temperature above the boiling point of liquid nitrogen.[10] Its molar ratio is 1 to 2 to 3 for yttrium, barium, and copper and it has a unit cell consisting of subunits, which is the typical structure of perovskites. In particular, the subunits are three, overlapping and containing an yttrium atom at the center of the middle one and a barium atom at the center of the others. Therefore, yttrium and barium are stacked according to the sequence [Ba-Y-Ba], along an axis conventionally denoted by c, (the vertical direction in the figure on the right).

The resulting cell has an orthorhombic structure, unlike other superconducting cuprates that generally have a tetragonal structure. All the corner sites of the unit cell are occupied by copper, which has two different coordinates, Cu(1) and Cu(2), with respect to oxygen. It offers four possible crystallographic sites for oxygen: O(1), O(2), O(3), and O(4).[11]

History

Because these kind of materials are brittle it was difficult to create wires from them. After 2010, industrial manufacturers started to produce tapes,[12] with different layers encapsulating the ReBCO material,[13] opening the way to commercial uses.

In September 2021 Commonwealth Fusion Systems (CFS) created a test magnet with ReBCO tape that handled a current of 40,000 amperes, with a magnetic field of 20 tesla at 20 K.[14][15] One important innovation was to avoid insulating the tape, saving space and lowering required voltages. Another was the size of the magnet: 10 tons, far larger than any prior experiment. The magnet assembly consisted of 16 plates, called pancakes, each hosting a spiral winding of tape on one side and cooling channels on the other.[16]

In 2023, the National High Magnetic Field Laboratory generated 32 tesla with a ReBCO superconducting magnet.[17][18] A 40T superconducting magnet is under construction.

See also

References

  1. ^ Jha, Alok K.; Matsumoto, Kaname (2019). "Superconductive REBCO Thin Films and Their Nanocomposites: The Role of Rare-Earth Oxides in Promoting Sustainable Energy". Frontiers in Physics. 7: 82. Bibcode:2019FrP.....7...82J. doi:10.3389/fphy.2019.00082. ISSN 2296-424X.
  2. ^ Fisk, Z.; Thompson, J.D.; Zirngiebl, E.; Smith, J.L.; Cheong, S-W. (June 1987). "Superconductivity of rare earth-barium-copper oxides". Solid State Communications. 62 (11): 743–744. Bibcode:1987SSCom..62..743F. doi:10.1016/0038-1098(87)90038-X.
  3. ^ "New superconductors raise hope for fast development of compact fusion reactor". The Engineer. 14 August 2015. Retrieved 21 June 2020.
  4. ^ "To 20 Tesla and beyond: the high-temperature superconductors". CERN. Retrieved 2021-11-05.
  5. ^ van Nugteren, J.; Kirby, G.; Murtomäki, Jaakko Samuel. "Towards REBCO 20T+ Dipoles for Accelerators". ResearchGate. G. de Rijk, L. Rossi and A. Stenvall.
  6. ^ Kasuga, K.; Muralidhar, M.; Diko, P. (2016-01-01). "SEM and SEM by EDX Analysis of Air-Processed SmBa2Cu3Oy". Physics Procedia. 81: 41–44. Bibcode:2016PhPro..81...41K. doi:10.1016/j.phpro.2016.04.018.
  7. ^ Hari Babu, N.; Lo, W.; Cardwell, D. A. (1999-11-08). "The irreversibility behavior of NdBaCuO fabricated by top-seeded melt processing". Applied Physics Letters. 75 (19): 2981–2983. Bibcode:1999ApPhL..75.2981H. doi:10.1063/1.125208. Retrieved 2021-10-12.
  8. ^ Murakami, M.; Sakai, N.; Higuchi, T.; Yoo, S. I. (1996). "Melt-processed light rare earth element - Ba - Cu - O". Superconductor Science and Technology. 9 (12): 1015–1032. doi:10.1088/0953-2048/9/12/001. S2CID 250762176. Retrieved 2021-10-12.
  9. ^ Koblischka-Veneva, Anjela; Koblischka, Michael R.; Berger, Kévin; Nouailhetas, Quentin; Douine, Bruno; Muralidhar, Miryala; Murakami, Masato (August 2019). "Comparison of Temperature and Field Dependencies of the Critical Current Densities of Bulk YBCO, MgB₂, and Iron-Based Superconductors". IEEE Transactions on Applied Superconductivity. 29 (5): 1–5. Bibcode:2019ITAS...2900932K. doi:10.1109/TASC.2019.2900932. ISSN 1558-2515. S2CID 94789535.
  10. ^ Wu, M. K. (1987). "Superconductivity at 93 K in a new mixed-phase Y-Ba-Cu-O compound system at ambient pressure" (PDF). Physical Review Letters. 58 (9). J. R. Ashburn, C. J. Torng, P. H. Hor, R. L. Meng, L. Gao, Z. J. Huang, Y. Q. Wang, et C. W. Chu: 908–910. Bibcode:1987PhRvL..58..908W. doi:10.1103/PhysRevLett.58.908. PMID 10035069. S2CID 18428336.
  11. ^ Hazen, R. M.; Finger, L. W.; Angel, R. J.; Prewitt, C. T.; Ross, N. L.; Mao, H. K.; Hadidiacos, C. G.; Hor, P. H.; Meng, R. L.; Chu, C. W. (1987-05-01). "Crystallographic description of phases in the Y-Ba-Cu-O superconductor". Physical Review B. 35 (13): 7238–7241. Bibcode:1987PhRvB..35.7238H. doi:10.1103/PhysRevB.35.7238. PMID 9941012.
  12. ^ "ReBCO High Temperature Superconducting Tape". www.fusionenergybase.com. Retrieved 2021-11-05.
  13. ^ Barth, Christian; Mondonico, Giorgio (2015). "Electro-mechanical properties of ReBCO coated conductors from various industrial manufacturers at 77 K, self-field and 4.2 K, 19 T". Superconductor Science and Technology. 28 (4): 045011. arXiv:1502.06713. Bibcode:2015SuScT..28d5011B. doi:10.1088/0953-2048/28/4/045011. S2CID 118673085.
  14. ^ "Eni and Commonwealth Fusion Systems Abstract". www.eni.com. Retrieved 2021-12-02.
  15. ^ "MIT ramps 10-ton magnet up to 20 tesla in proof of concept for commercial fusion -- ANS / Nuclear Newswire". www.ans.org. Retrieved 2021-12-02.
  16. ^ "Tests show high-temperature superconducting magnets are ready for fusion". MIT News | Massachusetts Institute of Technology. 2024-03-04. Retrieved 2024-04-02.
  17. ^ Hall, Heather (July 3, 2023). "R&D 100 winner of the day: 32 Tesla Superconducting Magnet". R&D Magazine. Retrieved July 13, 2023.
  18. ^ "Meet the 32 Tesla Superconducting Magnet". National High Magnetic Field Laboratory. March 21, 2023. Retrieved July 13, 2023.
Quelle: http://en.wikipedia.org/wiki/Rare-earth_barium-copper_oxide