https://doi.org/10.1140/epjb/e2012-30422-6
Regular Article
Superconductivity at Tc = 44 K in Lix Fe2 Se2 (NH3)y
1
CPM, Institute of Physics, University of Augsburg,
86157
Augsburg,
Germany
2
Center for Electronic Correlations and Magnetism, Institute of
Physics, University of Augsburg, 86159
Augsburg,
Germany
3
Institute of Applied Physics, Academy of Sciences of
Moldova, MD 2028,
Chisinau, R.
Moldova
a e-mail: vladimir.tsurkan@physik.uni-augsburg.de
Received:
25
May
2012
Received in final form:
12
June
2012
Published online:
8
August
2012
Following a recent proposal by Burrard-Lucas et al. [arXiv:1203.5046] we intercalated FeSe with Li in liquid ammonia. We report on the synthesis of new LixFe2Se2(NH3)y phases as well as on their magnetic and superconducting properties. We suggest that the superconducting properties of these new hybride materials appear not to be influenced by the presence of electronically-innocent Li(NH2) molecules. Indeed, high onset temperatures of 44 K and shielding fractions of almost 80% were only obtained in samples containing exclusively Lix(NH3)y moieties acting simultaneously as electron donors and spacer units. The c-axis lattice parameter of the new intercalated phases is strongly enhanced when compared to the alkali-metal intercalated iron selenides A1−xFe2−ySe2 with A = K, Rb, Cs, Tl with Tc = 32 K.
Key words: Solid State and Materials
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2012
