Publication Date:
2012-07-09
Description:
Observation of superconductivity at 30∼46K in AxFe2Se2 (A = Li, Na, Ba, Sr, Ca, Yb, and Eu) Scientific Reports 2, 28052012 doi: 10.1038/srep00426 T. P. Ying X. L. Chen G. Wang S. F. Jin T. T. Zhou X. F. Lai H. Zhang W. Y. Wang New iron selenide superconductors by intercalating smaller-sized alkali metals (Li, Na) and alkaline earths using high-temperature routes have been pursued ever since the discovery of superconductivity at about 30 K in KFe2Se2, but all have failed so far. Here we demonstrate that a series of superconductors with enhanced Tc = 30∼46 K can be obtained by intercalating metals, Li, Na, Ba, Sr, Ca, Yb, and Eu in between FeSe layers by the ammonothermal method at room temperature. Analysis on their powder X-ray diffraction patterns reveals that all the main phases can be indexed based on body-centered tetragonal lattices with a∼3.755–3.831 Å while c∼15.99–20.54 Å. Resistivities show the corresponding sharp transitions at 45 K and 39 K for NaFe2Se2 and Ba0.8Fe2Se2, respectively, confirming their bulk superconductivity. These findings provide a new starting point for studying the properties of these superconductors and an effective synthetic route for the exploration of new superconductors as well.
Electronic ISSN:
2045-2322
Topics:
Natural Sciences in General
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