Fe-vacancy order and superconductivity in tetragonal [Beta]-Fe^sub 1-x^Se

Several superconducting transition temperatures in the range of 30-46 K were reported in the recently discovered intercalated FeSe system (A...Fe...Se..., A = K, Rb, Cs, Tl). Although the superconducting phases were not yet conclusively decided, more than one magnetic phase with particular orders of...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2014-01, Vol.111 (1), p.63
Main Authors: Chen, Ta-Kun, Chang, Chung-Chieh, Chang, Hsian-Hong, Fang, Ai-Hua, Wang, Chih-Han, Chao, Wei-Hsiang, Tseng, Chuan-Ming, Lee, Yung-Chi, Wu, Yu-Ruei, Wen, Min-Hsueh, Tang, Hsin-Yu, Chen, Fu-Rong, Wang, Ming-Jye, Wu, Maw-Kuen, Van Dyck, Dirk
Format: Article
Language:English
Subjects:
Analytical chemistry
Electromagnetics
Iron compounds
Microscopy
Phase transitions
Superconductivity
Temperature effects
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Summary:Several superconducting transition temperatures in the range of 30-46 K were reported in the recently discovered intercalated FeSe system (A...Fe...Se..., A = K, Rb, Cs, Tl). Although the superconducting phases were not yet conclusively decided, more than one magnetic phase with particular orders of iron vacancy and/or potassium vacancy were identified, and some were argued to be the parent phase. Here we show the discovery of the presence and ordering of iron vacancy in nonintercalated FeSe (PbO-type tetragonal β-Fe...Se). Three types of iron-vacancy order were found through analytical electron microscopy, and one was identified to be nonsuperconducting and magnetic at low temperature. This discovery suggests that the rich-phases found in A...Fe...Se... are not exclusive in Fe-Se and related superconductors. In addition, the magnetic β-Fe...Se phases with particular iron-vacancy orders are more likely to be the parent phase of the FeSe superconducting system instead of the previously assigned β-Fe...Te. (ProQuest: ... denotes formulae/symbols omitted.)
ISSN:0027-8424
1091-6490