Physics:Oxypnictide
In chemistry, oxypnictides are a class of materials composed of oxygen, a pnictogen (group-V, especially phosphorus and arsenic) and one or more other elements. Although this group of compounds has been recognized since 1995,[1] interest in these compounds increased dramatically after the publication of the superconducting properties of LaOFeP and LaOFeAs which were discovered in 2006[2] and 2008.[3][4] In these experiments the oxide was partly replaced by fluoride.
These and related compounds (e.g. the 122 iron arsenides) form a new group of iron-based superconductors known as iron pnictides or ferropnictides since the oxygen is not essential but the iron seems to be.
Oxypnictides have been patented as magnetic semiconductors in early 2006.[5]
The different subclasses of oxypnictides are oxynitrides, oxyphosphides, oxyarsenides, oxyantimonides, and oxybismuthides.
Structure
Many of the oxypnictides show a layered structure.[6] For example, LaFePO with layers of La3+O2− and Fe2+P3−.[2] This structure is similar to that of ZrCuSiAs, which is now the parent structure for most of the oxypnictide.[7]
Superconductivity
The first superconducting iron oxypnictide was discovered in 2006, based on phosphorus.[2] A drastic increase in the critical temperature was achieved when phosphorus was substituted by arsenic.[3] This discovery boosted the search for similar compounds, like the search for cuprate-based superconductors after their discovery in 1986.
The superconductivity of the oxypnictides seems to depend on the iron-pnictogen layers.
Some found in 2008 to be high-temperature superconductors (up to 55 K) of composition ReOTmPn, where Re is a rare earth, Tm is a transition metal and Pn is from group V e.g. As.[8]
| Material | Tc (K) |
|---|---|
| LaO0.89F0.11FeAs | 26[9] |
| LaO0.9F0.2FeAs | 28.5[10] |
| CeFeAsO0.84F0.16 | 41[9] |
| SmFeAsO0.9F0.1 | 43[9] |
| La0.5Y0.5FeAsO0.6 | 43.1[11] |
| NdFeAsO0.89F0.11 | 52[9] |
| PrFeAsO0.89F0.11 | 52[12] |
| GdFeAsO0.85 | 53.5[13] |
| SmFeAsO~0.85 | 55[14] |
Tests in magnetic fields up to 45 teslas[15][16] suggest the upper critical field of LaFeAsO0.89F0.11 may be around 64 T. A different lanthanum-based material tested at 6 K predicts an upper critical field of 122 T in La0.8K0.2FeAsO0.8F0.2.[10]
Practical use
Because of the brittleness of the oxypnictides, superconducting wires are formed using the powder-in-tube process (using iron tubes).[17]
See also
- Chemistry:Charge-transfer complex – Association of molecules in which a fraction of electronic charge is transferred between them
- Physics:Color superconductivity – Predicted phase in quark matter in quarks
- Physics:Kondo effect – Physical phenomenon due to impurities
- Physics:Magnetic sail – Proposed spacecraft propulsion method
- Organization:National Superconducting Cyclotron Laboratory – Building in Michigan, United States
- Physics:Spallation Neutron Source – Accelerator-based neutron source in Oak Ridge, Tennessee, USA
- Physics:Superconducting radio frequency – Technique used to attain a high quality factor in resonant cavities
- Physics:Superfluid film – Thin layer of liquid in a superfluid state
- Engineering:Timeline of low-temperature technology – Aspect of history
References
- ↑ Zimmer, Barbara I.; Jeitschko, Wolfgang; Albering, Jörg H.; Glaum, Robert; Reehuis, Manfred (1995). "The rate earth transition metal phosphide oxides LnFePO, LnRuPO and LnCoPO with ZrCuSiAs type structure". Journal of Alloys and Compounds 229 (2): 238–242. doi:10.1016/0925-8388(95)01672-4.
- ↑ 2.0 2.1 2.2 Kamihara, Y; Hiramatsu, H; Hirano, M; Kawamura, R; Yanagi, H; Kamiya, T; Hosono, H (2006). "Iron-Based Layered Superconductor: LaOFeP". J. Am. Chem. Soc. 128 (31): 10012–10013. doi:10.1021/ja063355c. PMID 16881620.
- ↑ 3.0 3.1 Takahashi, H; Igawa, K; Arii, K; Kamihara, Y; Hirano, M; Hosono, H (2008). "Superconductivity at 43 K in an iron-based layered compound LaO1−xFxFeAs". Nature 453 (7193): 376–378. doi:10.1038/nature06972. PMID 18432191. Bibcode: 2008Natur.453..376T.
- ↑ Day, Charles (2008). "New family of quaternary iron-based compounds superconducts at tens of kelvin". Physics Today 61 (5): 11–12. doi:10.1063/1.2930719. Bibcode: 2008PhT....61e..11D.
- ↑ H. Hosono et al. (2006) Magnetic semiconductor material European Patent Application EP1868215
- ↑ Ozawa, T. C.; Kauzlarich, S. M. (2008). "Chemistry of layered d-metal pnictide oxides and their potential as candidates for new superconductors". Sci. Technol. Adv. Mater. 9 (3): 033003. doi:10.1088/1468-6996/9/3/033003. PMID 27877997. Bibcode: 2008STAdM...9c3003O.
- ↑ Tegel, Marcus; Bichler, Daniel; Johrendt, Dirk (2008). "Synthesis, crystal structure and superconductivity of LaNiPO". Solid State Sciences 10 (2): 193–197. doi:10.1016/j.solidstatesciences.2007.08.016. Bibcode: 2008SSSci..10..193T.
- ↑ Ren, Z. A.; Yang, J.; Lu, W.; Yi, W.; Che, G. C.; Dong, X. L.; Sun, L. L.; Zhao, Z. X. (2008). "Samarium based SmFeAsO1−xFx". Materials Research Innovations 12 (3): 105. doi:10.1179/143307508X333686. Bibcode: 2008MatRI..12..105R.
- ↑ 9.0 9.1 9.2 9.3 Ishida, Kenji; Nakai, Yusuke; Hosono, Hideo (2009). "To What Extent Iron-Pnictide New Superconductors Have Been Clarified: A Progress Report". J. Phys. Soc. Jpn. 78 (6): 062001. doi:10.1143/JPSJ.78.062001. Bibcode: 2009JPSJ...78f2001I.
- ↑ 10.0 10.1 Prakash, J.; Singh, S. J.; Samal, S. L.; Patnaik, S.; Ganguli, A. K. (2008). "Potassium fluoride doped LaOFeAs multi-band superconductor: Evidence of extremely high upper critical field". EPL 84 (5): 57003. doi:10.1209/0295-5075/84/57003. Bibcode: 2008EL.....8457003P.
- ↑ Shirage, Parasharam M.; Miyazawa, Kiichi; Kito, Hijiri; Eisaki, Hiroshi; Iyo, Akira (2008). "Superconductivity at 43 K at ambient pressure in the iron-based layered compound La1‑xYxFeAsOy". Physical Review B 78 (17): 172503. doi:10.1103/PhysRevB.78.172503. Bibcode: 2008PhRvB..78q2503S.
- ↑ Ren, Z. A.; Yang, J.; Lu, W.; Yi, W.; Che, G. C.; Dong, X. L.; Sun, L. L.; Zhao, Z. X. (2008). "Superconductivity at 52 K in iron based F doped layered quaternary compound Pr[O1–xFx]FeAs". Materials Research Innovations 12 (3): 105. doi:10.1179/143307508X333686. Bibcode: 2008MatRI..12..105R.
- ↑ Yang, Jie; Li, Zheng-Cai; Lu, Wei; Yi, Wei; Shen, Xiao-Li; Ren, Zhi-An; Che, Guang-Can; Dong, Xiao-Li et al. (2008). "Superconductivity at 53.5 K in GdFeAsO1−δ". Superconductor Science and Technology 21 (8): 082001. doi:10.1088/0953-2048/21/8/082001. Bibcode: 2008SuScT..21h2001Y.
- ↑ Ren, Zhi-An; Che, Guang-Can; Dong, Xiao-Li; Yang, Jie; Lu, Wei; Yi, Wei; Shen, Xiao-Li; Li, Zheng-Cai et al. (2008). "Superconductivity and phase diagram in iron-based arsenic-oxides ReFeAsO1−δ (Re = rare-earth metal) without fluorine doping". EPL 83 (1): 17002. doi:10.1209/0295-5075/83/17002. Bibcode: 2008EL.....8317002R.
- ↑ "High-temp superconductors pave way for 'supermagnets'". planetanalog. May 29, 2008. http://www.planetanalog.com/news/showArticle.jhtml?articleID=208401297.[yes|permanent dead link|dead link}}]
- ↑ Hunte, F; Jaroszynski, J; Gurevich, A; Larbalestier, D. C.; Jin, R; Sefat, A. S.; McGuire, M. A.; Sales, B. C. et al. (2008). "Two-band superconductivity in LaFeAsO0.89F0.11 at very high magnetic fields". Nature 453 (7197): 903–905. doi:10.1038/nature07058. PMID 18509332. Bibcode: 2008Natur.453..903H.
- ↑ Gao, Zhaoshun; Wang, Lei; Qi, Yanpeng; Wang, Dongliang; Zhang, Xianping; Ma, Yanwei (2008). "Preparation of LaFeAsO0.9F0.1 wires by the powder-in-tube method". Superconductor Science and Technology 21 (10): 105024. doi:10.1088/0953-2048/21/10/105024. Bibcode: 2008SuScT..21j5024G.
External links
- Hosono at JST Has diagram of LaO & FeAs layers in LaOFeAs
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