Possibility of local pair existence in optimally doped SmFeAsO1-х in pseudogap regime
A.L. Solovjov, V.N. Svetlov, and V.B. Stepanov
B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
S.L. Sidorov, V.Yu. Tarenkov, and A.I. D’yachenko
A. Galkin Institute for Physics and Engineering of the National Academy of Sciences of Ukraine 72 R. Luxemburg, Donetsk 83114, Ukraine
Institut für Festkörperphysik, Leibniz Universität, Hannover Appelstr. 2, D-30167 Hannover, Germany pos Анотація:
Received January 10, 2011
We report the analysis of pseudogap Δ* derived from resistivity experiments in FeAs-based superconductor SmFeAsO0.85, having a critical temperature Tc = 55 K. Rather specific dependence Δ*(T) with two representative temperatures followed by a minimum at about 120 K was observed. Below Ts ≈ 147 K, corresponding to the structural transition in SmFeAsO, Δ*(T) decreases linearly down to the temperature TAFM ≈ 133 K. This last peculiarity can likely be attributed to the antiferromagnetic (AFM) ordering of Fe spins. It is believed that the found behavior can be explained in terms of Machida, Nokura, and Matsubara theory developed for the AFM superconductors.
PACS: 74.25.−q Properties of superconductors; PACS: 74.40.–n Fluctuation phenomena; PACS: 74.78.Fk Multilayers, superlattices, heterostructures; PACS: 74.70.−b Superconducting materials other than cuprates.
Key words: high-Tc superconductivity, FeAs-based superconductors, pseudogap, local pairs.