Influence of Sn doping on the phase formation and superconductivity of FeSe sub(0.93)

Sn doped FeSe sub(0.93) bulk samples were prepared by solid-state reaction in Ar atmosphere. The result suggests that Sn does not actually enter the crystal lattice of beta -FeSe, existing as an inclusion SnSe instead. Although the existence of impurities such as Fe sub(7)Se sub(8), Fe sub(3)O sub(4...

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Bibliographic Details
Published in:Journal of alloys and compounds 2014-03, Vol.588, p.418-421
Main Authors: Chen, Ning, Ma, Zongqing, Liu, Yongchang, Li, Xiaoting, Cai, Qi, Li, Huijun, Yu, Liming
Format: Article
Language:English
Subjects:
Alloys
Crystal lattices
Formations
Grains
Inclusions
Superconductivity
Superconductors
Tin
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Summary:Sn doped FeSe sub(0.93) bulk samples were prepared by solid-state reaction in Ar atmosphere. The result suggests that Sn does not actually enter the crystal lattice of beta -FeSe, existing as an inclusion SnSe instead. Although the existence of impurities such as Fe sub(7)Se sub(8), Fe sub(3)O sub(4) and SnSe is harmful to the superconductivity of beta -FeSe, the T sub(c) of the Sn doped FeSe sub(0.93) samples is not suppressed compared to the undoped one, quite different from previous studies on the metal doped FeSe superconductors. According to the thermal analysis, Sn was firstly melt and then reacted with Se forming SnSe. The presence of SnSe can obviously accelerate the subsequent formation of iron selenide. XRD result indicates that Sn addition can also promote the growth of beta -FeSe grains along (0 0 1), (1 0 1), (1 1 2) crystal planes and expedites the transformation from Fe sub(7)Se sub(8) to beta -FeSe, the superconducting phase. Morphology observation also displays enlarged beta -FeSe grains and their better connection with each other in the Sn doped samples. All the factors mentioned above are contributed to the relative high T sub(c) of Sn-doped FeSe sub(0.93) samples. The present work suggests that Sn might be a promising element to improve the superconductivity of FeSe sub(1) sub(-) sub(x) if the amount of addition as well as the sintering process is further optimized.
ISSN:0925-8388
DOI:10.1016/j.jallcom.2013.11.121