Rare-earth barium copper oxide

Any rare-earth element can be used in a ReBCO; popular choices include yttrium (YBCO), lanthanum (LBCO), samarium (Sm123),{{Cite journal |last1=Kasuga |first1=K. |last2=Muralidhar |first2=M. |last3=Diko |first3=P. |date=2016-01-01 |title=SEM and SEM by EDX Analysis of Air-Processed SmBa2Cu3Oy |journal=Physics Procedia |volume=81 |pages=41–44 |bibcode=2016PhPro..81...41K |doi=10.1016/j.phpro.2016.04.018 |doi-access=free}} neodymium (Nd123 and Nd422),{{Cite journal |last1=Hari Babu |first1=N. |last2=Lo |first2=W. |last3=Cardwell |first3=D. A. |date=1999-11-08 |title=The irreversibility behavior of NdBaCuO fabricated by top-seeded melt processing |url=https://aip.scitation.org/doi/10.1063/1.125208 |journal=Applied Physics Letters |volume=75 |pages=2981–2983 |bibcode=1999ApPhL..75.2981H |doi=10.1063/1.125208 |number=19 |access-date=2021-10-12|url-access=subscription }} gadolinium (Gd123) and europium (Eu123),{{Cite journal |last1=Murakami |first1=M. |last2=Sakai |first2=N. |last3=Higuchi |first3=T. |last4=Yoo |first4=S. I. |year=1996 |title=Melt-processed light rare earth element - Ba - Cu - O |url=https://iopscience.iop.org/article/10.1088/0953-2048/9/12/001/meta |journal=Superconductor Science and Technology |volume=9 |pages=1015–1032 |doi=10.1088/0953-2048/9/12/001 |s2cid=250762176 |number=12 |access-date=2021-10-12|url-access=subscription }} where the numbers among parenthesis indicate the molar ratio among rare-earth, barium and copper.

File:YBCO-IG A vs T.svg/cm²) vs absolute temperature (K), at different magnetic field (T).{{Cite journal|last1=Koblischka-Veneva|first1=Anjela|last2=Koblischka|first2=Michael R.|last3=Berger|first3=Kévin|last4=Nouailhetas|first4=Quentin|last5=Douine|first5=Bruno|last6=Muralidhar|first6=Miryala|last7=Murakami|first7=Masato|date=August 2019|title=Comparison of Temperature and Field Dependencies of the Critical Current Densities of Bulk YBCO, MgB₂, and Iron-Based Superconductors|url=https://ieeexplore.ieee.org/document/8649756|journal=IEEE Transactions on Applied Superconductivity|volume=29|issue=5|pages=1–5|doi=10.1109/TASC.2019.2900932|bibcode=2019ITAS...2900932K|s2cid=94789535|issn=1558-2515}}|left]]

The most famous ReBCO is yttrium barium copper oxide, YBa₂Cu₃O_7−x (or Y123), the first superconductor found with a critical temperature above the boiling point of liquid nitrogen.{{Cite journal|last=Wu|first=M. K.|others=J. R. Ashburn, C. J. Torng, P. H. Hor, R. L. Meng, L. Gao, Z. J. Huang, Y. Q. Wang, et C. W. Chu|title=Superconductivity at 93 K in a new mixed-phase Y-Ba-Cu-O compound system at ambient pressure|url=https://www.sfu.ca/~simonw/phys431/references/superconductors/wu_YBCO_PRL1987.pdf|journal=Physical Review Letters|year=1987|volume=58|issue=9|pages=908–910|doi=10.1103/PhysRevLett.58.908|pmid=10035069 |bibcode=1987PhRvL..58..908W|s2cid=18428336 }} 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 at the top 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).{{Cite journal|last1=Hazen|first1=R. M.|last2=Finger|first2=L. W.|last3=Angel|first3=R. J.|last4=Prewitt|first4=C. T.|last5=Ross|first5=N. L.|last6=Mao|first6=H. K.|last7=Hadidiacos|first7=C. G.|last8=Hor|first8=P. H.|last9=Meng|first9=R. L.|last10=Chu|first10=C. W.|date=1987-05-01|title=Crystallographic description of phases in the Y-Ba-Cu-O superconductor|url=https://link.aps.org/doi/10.1103/PhysRevB.35.7238|journal=Physical Review B|volume=35|issue=13|pages=7238–7241|doi=10.1103/PhysRevB.35.7238|pmid=9941012|bibcode=1987PhRvB..35.7238H|url-access=subscription}}

Because these kind of materials are brittle it was difficult to create wires from them. After 2010, industrial manufacturers started to produce tapes,{{Cite web|title=ReBCO High Temperature Superconducting Tape|url=https://www.fusionenergybase.com/concept/rebco-high-temperature-superconducting-tape/|access-date=2021-11-05|website=www.fusionenergybase.com|language=en}} with different layers encapsulating the ReBCO material,{{Cite journal|last1=Barth|first1=Christian|last2=Mondonico|first2=Giorgio|title=Electro-mechanical properties of ReBCO coated conductors from various industrial manufacturers at 77 K, self-field and 4.2 K, 19 T |url=https://www.researchgate.net/publication/272358146|journal=Superconductor Science and Technology|year=2015|volume=28|issue=4|page=045011|doi=10.1088/0953-2048/28/4/045011|arxiv=1502.06713|bibcode=2015SuScT..28d5011B|s2cid=118673085}} 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.{{Cite web|title=Eni and Commonwealth Fusion Systems Abstract|url=https://www.eni.com/en-IT/operations/collaboration-commonwealth-fusion-systems.html|access-date=2021-12-02|website=www.eni.com|language=en}}{{Cite web|title=MIT ramps 10-ton magnet up to 20 tesla in proof of concept for commercial fusion -- ANS / Nuclear Newswire|url=https://www.ans.org/news/article-3240/mit-ramps-10ton-magnet-up-to-20-tesla-in-proof-of-concept-for-commercial-fusion/|access-date=2021-12-02|website=www.ans.org}} 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.{{Cite web |date=2024-03-04 |title=Tests show high-temperature superconducting magnets are ready for fusion |url=https://news.mit.edu/2024/tests-show-high-temperature-superconducting-magnets-fusion-ready-0304 |access-date=2024-04-02 |website=MIT News {{!}} Massachusetts Institute of Technology |language=en}}

In 2023, the National High Magnetic Field Laboratory generated 32 tesla with a ReBCO superconducting magnet.{{cite journal |first= Heather |last= Hall |title= R&D 100 winner of the day: 32 Tesla Superconducting Magnet |url= https://www.rdworldonline.com/rd-100-winner-of-the-day-32-tesla-superconducting-magnet/ |journal= R&D Magazine |date= July 3, 2023 |access-date= July 13, 2023}}{{cite web |url= https://nationalmaglab.org/about-the-maglab/around-the-lab/meet-the-magnets/meet-the-32-tesla-superconducting-magnet/ |title= Meet the 32 Tesla Superconducting Magnet |publisher= National High Magnetic Field Laboratory |date= March 21, 2023 |access-date= July 13, 2023}} A 40T superconducting magnet is under construction.

In June 2024, the first plasma was achieved in the HH70 tokamak, developed by the China-based fusion energy company Energy Singularity. Using ReBCO as material for the superconductors enabled the company to reduce the size of the HH70 tokamak to two percent of conventional tokamaks.{{Cite web |last=Paleja |first=Ameya |title=World’s 1st high-temperature superconducting tokamak built in China |url=https://interestingengineering.com/energy/china-commercial-tokamak-nuclear-fusion |access-date=2025-02-12 |website=Interesting Engineering |language=en}}

• Cuprate superconductor
• List of superconductors

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Category:Barium compounds

Category:Copper compounds

Category:High-temperature superconductors

Category:Oxides