Cuprate superconductor
Cuprate superconductors are high-temperature superconductors made of layers of copper oxides (CuO2) alternating with layer of charge reservoirs (CR), which are oxides of other metals.
History
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Interest in cuprates sharply increased in 1986 with the discovery of high-temperature superconductivity in the non-stoichiometric cuprate lanthanum barium copper oxide. The Tc for this material was 35 K, well above the previous record of 23 K.[1] Thousands of publications examine the superconductivity in cuprates between 1986 and 2001,[2] and Bednorz and Müller were awarded the Nobel Prize in Physics only a year after their discovery.[3]
From 1986, many cuprate superconductors were identified, and can be put into three groups on a phase diagram critical temperature vs. oxygen hole content and copper hole content:
- lanthanum barium- (LB-CO), Tc=-240 °C (35 K).
- yttrium barium- (YB-CO), Tc=-215 °C (60 K).
- the Bi, Tl, Hg-based:
- bismuth strontium calcium- (BiSC-CO), Tc=-180 °C (95 K).
- thallium barium calcium- (TBC-CO), Tc=-150 °C (125 K).[4]
- mercury barium calcium- (HGBC-CO) 1993, with Tc=-140 °C (135 K), currently the highest cuprate critical temperature.[5][6]
Structure
![](../I/m/Bi2212_Unit_Cell.png)
Cuprate superconductors usually feature copper oxides in both the oxidation states 3+ and 2+. For example, YBa2Cu3O7 is described as Y3+(Ba2+)2(Cu3+)(Cu2+)2(O2−)7. All superconducting cuprates are layered materials having a complex structure described as a superlattice of superconducting CuO2 layers separated by spacer layers, where the misfit strain between different layers and dopants in the spacers induce a complex heterogeneity that in the superstripes scenario is intrinsic for high-temperature superconductivity.
Applications
BSCCO superconductors already have large-scale applications. For example, tens of kilometers of BSCCO-2223 at 77 K superconducting wires are being used in the current leads of the Large Hadron Collider at CERN.[7] (but the main field coils are using metallic lower temperature superconductors, mainly based on niobium–tin).
See also
Bibliography
References
- J. G. Bednorz; K. A. Mueller (1986). "Possible high TC superconductivity in the Ba-La-Cu-O system". Z. Phys. B. 64 (2): 189–193. Bibcode:1986ZPhyB..64..189B. doi:10.1007/BF01303701. no-break space character in
|author1=
at position 3 (help); no-break space character in|author2=
at position 3 (help) - Mark Buchanan (2001). "Mind the pseudogap". Nature. 409 (6816): 8–11. doi:10.1038/35051238. PMID 11343081.
- Nobel prize autobiography.
- Sheng, Z. Z.; Hermann A. M. (1988). "Bulk superconductivity at 120 K in the Tl–Ca/Ba–Cu–O system". Nature. 332 (6160): 138–139. Bibcode:1988Natur.332..138S. doi:10.1038/332138a0.
- Schilling, A.; Cantoni, M.; Guo, J. D.; Ott, H. R. (1993). "Superconductivity above 130 K in the Hg–Ba–Ca–Cu–O system". Nature. 363 (6424): 56–58. Bibcode:1993Natur.363...56S. doi:10.1038/363056a0.
- Lee, Patrick A. (2008). "From high temperature superconductivity to quantum spin liquid: progress in strong correlation physics". Reports on Progress in Physics. 71: 012501. arXiv:0708.2115. Bibcode:2008RPPh...71a2501L. doi:10.1088/0034-4885/71/1/012501.
- Amalia Ballarino (November 23, 2005). "HTS materials for LHC current leads". CERN.