%0 Journal Article
%T Synthesis of a new alkali metal-organic solvent intercalated iron selenide superconductor with Tc{\approx}45K
%A A. Krzton-Maziopa
%A E. V. Pomjakushina
%A V. Yu. Pomjakushin
%A F. von Rohr
%A A. Schilling
%A K. Conder
%J Physics
%D 2012
%I arXiv
%R 10.1088/0953-8984/24/38/382202
%X We report on a new iron selenide superconductor with a TC onset of 45K and the nominal composition Lix(C5H5N)yFe2-zSe2, synthesized via intercalation of dissolved alkaline metal in anhydrous pyridine at room temperature. This superconductor exhibits a broad transition, reaching zero resistance at 10K. Magnetization measurements reveal a superconducting shielding fraction of approximately 30%. Analogous phases intercalated with Na, K and Rb were also synthesized and characterized. The superconducting transition temperature of Lix(C5H5N)yFe2-zSe2 is clearly enhanced in comparison to the known superconductors FeSe0.98 (Tc ~ 8K) and AxFe2-ySe2 (TC ~ 27-32K) and is in close agreement with critical temperatures recently reported for Lix(NH3)yFe2-zSe2. Post-annealing of intercalated material (Lix(C5H5N)yFe2-zSe2) at elevated temperatures drastically enlarges the c-parameter of the unit cell (~44%) and increases the amount of superconducting shielding fraction to nearly 100%. Our findings indicate a new synthesis road leading to possibly even higher critical temperatures in this class of materials by intercalation of organic compounds between Fe-Se layers.
%U http://arxiv.org/abs/1206.7022v1