المؤلفون: Yong-Kang, Luo, Yu-Ke, Li, Cao, Wang, Xiao, Lin, Jian-Hui, Dai, Guang-Han, Cao, Zhu-An, Xu

المصدر: Chinese Physics B; Aug2013, Vol. 22 Issue 8, p087415-087431, 17p

مصطلحات موضوعية: SUPERCONDUCTIVITY, CHALCOGENIDES, SUPERCONDUCTORS, KONDO effect, ANTIFERROMAGNETIC materials

مستخلص: The recent discovery of high-temperature superconductivity in iron-based pnictides (chalcogenides) not only triggers tremendous enthusiasm in searching for new superconducting materials, but also opens a new avenue to the study of the Kondo physics. CeFeAsO is a parent compound of the 1111-type iron-based superconductors. It shows 3d-antiferromagnetic (AFM) ordering below ∼ 139 K and 4f-AFM ordering below ∼ 4 K. On the other hand, the phosphide CeFePO is a ferromagnetically correlated heavy-fermion (HF) metal with Kondo scale TK ∼ 10 K. These properties set up a new platform for research of the interplay among magnetism, Kondo effect, and superconductivity (SC). In this review, we present the recent progress in the study of chemical pressure effect in CeFeAsO1−yFy (y = 0 and 0.05). This P/As-doping in CeFeAsO serves as an effective controlling parameter which leads to two magnetic critical points, xc1 ≃ 0.4 and xc2 ≃ 0.92, associated with suppression of 3d and 4f magnetism, respectively. We also observe a turning point of AFM-FM ordering of Ce³⁺ moment at xc3 ≃ 0.37. The SC is absent in the phase diagram, which is attributed to the destruction to Cooper pair by Ce-FM fluctuations in the vicinity of xc1. We continue to investigate CeFeAs1−xPxO0.95F0.05. With the separation of xc1 and xc3, this chemical pressure results in a broad SC region 0≤ x ≤ 0.53, while the original HF behavior is driven away by 5% F⁻ doping. Different roles of P and F dopings are addressed, and the interplay between SC and Ce-4f magnetism is also discussed. [ABSTRACT FROM AUTHOR]

: Copyright of Chinese Physics B is the property of IOP Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Hao, Jiang, Yun-Lei, Sun, Zhu-An, Xu, Guang-Han, Cao

المصدر: Chinese Physics B; Aug2013, Vol. 22 Issue 8, p087410-087420, 11p

مصطلحات موضوعية: HIGH-temperature superconducting filters, CHALCOGENIDES, IRON-based superconductors, STRUCTURAL design, HIGH temperature superconductors, IRON compounds

مستخلص: The second class of high-temperature superconductors (HTSCs), iron-based pnictides and chalcogenides, necessarily contain Fe2X2 (“X" refers to a pnictogen or a chalcogen element) layers, just like the first class of HTSCs which possess the essential CuO2 sheets. So far, dozens of iron-based HTSCs, classified into nine groups, have been discovered. In this article, the crystal-chemistry aspects of the known iron-based superconductors are reviewed and summarized by employing “hard and soft acids and bases (HSAB)" concept. Based on these understandings, we propose an alternative route to exploring new iron-based superconductors via rational structural design. [ABSTRACT FROM AUTHOR]

: Copyright of Chinese Physics B is the property of IOP Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)