| rdfs:comment
| - Les supraconducteurs à base de fer (FeSC) sont des composés chimiques contenant du fer dont les propriétés supraconductrices ont été découvertes en 2006. Ce type de supraconducteurs est basé sur des couches conductrices de fer et d'un pnictogène (éléments chimiques du groupe 15 du tableau périodique) et pourrait être la nouvelle génération de supraconducteurs à haute température. (fr)
- 鉄系超伝導物質（てつけいちょうでんどうぶっしつ）は、鉄を含み超伝導現象を示す化合物。銅酸化物以外では、二ホウ化マグネシウムなどを抑え、2016年現在最も超伝導転移温度（Tc）の高い高温超伝導物質である。研究が活発化した2008年の1年間でTcが2倍以上に急上昇したことから、さらなる研究の発展が期待されている。 (ja)
- Сверхпроводники на основе железа (Iron-based superconductors, FeSC) — железосодержащие химические соединения, обладающие сверхпроводимостью. Были открыты в 2006 году. Примечательны осуществлением сверхпроводимости не по плоскостям CuO2 — единственной её реализацией в оксидных материалах. (ru)
- Iron-based superconductors (FeSC) are iron-containing chemical compounds whose superconducting properties were discovered in 2006.In 2008, led by recently discovered iron pnictide compounds (originally known as oxypnictides), they were in the first stages of experimentation and implementation. (Previously most high-temperature superconductors were cuprates and being based on layers of copper and oxygen sandwiched between other substances (La, Ba, Hg)). The oxypnictides such as LaOFeAs are often referred to as the '1111' pnictides. (en)
- 철-비소 기반 초전도체에 대해 설명한다. 2008년 초 철 기반의 새로운 초전도체가 일본의 Hosono그룹에서 보고되었다 (Y. KamiharaT., 2008). 이는 LaFeAsO의 화학식을 가지는 금속을 띠는 물질이지만 산소 자리에 불소가 도핑되면서 초전도 현상이 나타나는 것을 보였다. 원자의 배열 구조는 편형 형태로서 LaO 층과 FeAs층이 번갈아가며 쌓여있다. F원자가 산소 자리를 채우면서 전자 하나가 많아지고 이것이 FeAs층에 전자를 공급하여 전하를 운송하게 되며 이를 통해서 초전도 현상이 나타나게 된다. 이후 이와 비슷한 성질을 가지는 물질이 AFe2As2 (A = Sr, Ca, Ba, Eu)구조에서도 발견되었다. 이 물질 또한 초전도 현상을 보이지 않지만 정공 또는 전자를 도핑하거나 압력을 가해주면 초전도 현상을 보이게 된다. 또한 원래의 물질은 온도가 내려감에 따라 스핀밀도파동(spin density wave)전이를 보이는데 위의 세 가지 요소에 따라 이것이 점차 억제되고 서서히 초전도 현상이 나타난다. 일부 아직까지 확실하지는 않지만 초전도 현상과 스핀밀도파동 전이가 공존하는 경우도 보고되고 있다. (ko)
- 鐵基超導體是指化合物中含有鐵，在低溫時具有超導現象，且鐵扮演形成超導的主體的材料。2006年日本東京工業大學細野秀雄教授的團隊發現第一個以鐵為超導主體的化合物LaFeOP，打破以往普遍認定鐵元素不利形成超導迷思。 根據BCS理論，產生超導性的必要條件是材料中的電子必須配對，這樣配對的電子稱為庫柏對。庫柏對中的兩個電子自旋相反，所以總自旋為零，因而科學家認為超導性與鐵磁性可能無法共存，材料中如果加入磁性元素（如鐵、鎳）會大大降低超導性。鐵基超導體雖然含有鐵元素且是產生超導的主體，但是鐵和其他元素（如砷、硒）形成鐵基平面後，已不再具有鐵磁性。 (zh)
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| has abstract
| - Iron-based superconductors (FeSC) are iron-containing chemical compounds whose superconducting properties were discovered in 2006.In 2008, led by recently discovered iron pnictide compounds (originally known as oxypnictides), they were in the first stages of experimentation and implementation. (Previously most high-temperature superconductors were cuprates and being based on layers of copper and oxygen sandwiched between other substances (La, Ba, Hg)). This new type of superconductors is based instead on conducting layers of iron and a pnictide (chemical elements in group 15 of the periodic table, here typically arsenic (As) and phosphorus (P)) and seems to show promise as the next generation of high temperature superconductors. Much of the interest is because the new compounds are very different from the cuprates and may help lead to a theory of non-BCS-theory superconductivity. More recently these have been called the ferropnictides. The first ones found belong to the group of oxypnictides. Some of the compounds have been known since 1995, and their semiconductive properties have been known and patented since 2006. It has also been found that some iron chalcogens superconduct. The undoped β-FeSe is the simplest iron-based superconductor but with the diverse properties. It has a critical temperature (Tc) of 8 K at normal pressure, and 36.7 K under high pressure and by means of intercalation. The combination of both intercalation and pressure results in re-emerging superconductivity at 48 (see and references therein). A subset of iron-based superconductors with properties similar to the oxypnictides, known as the 122 iron arsenides, attracted attention in 2008 due to their relative ease of synthesis. The oxypnictides such as LaOFeAs are often referred to as the '1111' pnictides. The crystalline material, known chemically as LaOFeAs, stacks iron and arsenic layers, where the electrons flow, between planes of lanthanum and oxygen. Replacing up to 11 percent of the oxygen with fluorine improved the compound — it became superconductive at 26 kelvin, the team reports in the March 19, 2008 Journal of the American Chemical Society. Subsequent research from other groups suggests that replacing the lanthanum in LaOFeAs with other rare earth elements such as cerium, samarium, neodymium and praseodymium leads to superconductors that work at 52 kelvin. Iron pnictide superconductors crystallize into the [FeAs] layered structure alternating with spacer or charge reservoir block. The compounds can thus be classified into “1111” system RFeAsO (R: the rare earth element) including LaFeAsO, SmFeAsO, PrFeAsO, etc.; “122” type BaFe2As2, SrFe2As2 or CaFe2As2; “111” type LiFeAs, NaFeAs, and LiFeP. Doping or applied pressure will transform the compounds into superconductors. Compounds such as Sr2ScFePO3 discovered in 2009 are referred to as the '42622' family, as FePSr2ScO3. Noteworthy is the synthesis of (Ca4Al2O6−y)(Fe2Pn2) (or Al-42622(Pn); Pn = As and P) using high-pressure synthesis technique. Al-42622(Pn) exhibit superconductivity for both Pn = As and P with the transition temperatures of 28.3 K and 17.1 K, respectively. The a-lattice parameters of Al-42622(Pn) (a = 3.713 Å and 3.692 Å for Pn = As and P, respectively) are smallest among the iron-pnictide superconductors. Correspondingly, Al-42622(As) has the smallest As-Fe-As bond angle (102.1°) and the largest As distance from the Fe planes (1.5 Å). High-pressure technique also yields (Ca3Al2O5−y)(Fe2Pn2) (Pn = As and P), the first reported iron-based superconductors with the perovskite-based '32522' structure. The transition temperature (Tc) is 30.2 K for Pn = As and 16.6 K for Pn = P. The emergence of superconductivity is ascribed to the small tetragonal a-axis lattice constant of these materials. From these results, an empirical relationship was established between the a-axis lattice constant and Tc in iron-based superconductors. In 2009, it was shown that undoped iron pnictides had a magnetic quantum critical point deriving from competition between electronic localization and itinerancy. (en)
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