Iron-based superconductors include pnictides and chalcogenides.So far,the chalcogenides are much fewer in number[1],thus it is particularly valuable to find new superconductors in iron chalcogenides,for the'ultima...Iron-based superconductors include pnictides and chalcogenides.So far,the chalcogenides are much fewer in number[1],thus it is particularly valuable to find new superconductors in iron chalcogenides,for the'ultimate'understanding of iron-based superconductivity.The tetragonal binary iron selenide(β-Fe1+δSe)is the structurally simplest iron-based superconductor with a superconducting critical temperature(Tc)of 8.5 K at ambient pressure[2].By intercalation of alkali metal ions into展开更多
Mossbauer spectroscopy was used to probe the site-specific information of a K0.84Fe1.99Se2 superconductor. A spin excitation gap, △E≈5.5 meV, is observed by analyzing the temperature dependence of the hyperfine magn...Mossbauer spectroscopy was used to probe the site-specific information of a K0.84Fe1.99Se2 superconductor. A spin excitation gap, △E≈5.5 meV, is observed by analyzing the temperature dependence of the hyperfine magnetic field （HMF） at the iron site within the spin wave theory. Using the simple model suggested in the literature, the temperature dependence of the HMF is well reproduced, suggesting that, below room temperature, the alkali metal intercalated iron selenide superconductors can be regarded as ferromagnetically coupled spin blocks that interact with each other antiferromagnetically to form the observed checkerboard-like magnetic structure.展开更多
文摘Iron-based superconductors include pnictides and chalcogenides.So far,the chalcogenides are much fewer in number[1],thus it is particularly valuable to find new superconductors in iron chalcogenides,for the'ultimate'understanding of iron-based superconductivity.The tetragonal binary iron selenide(β-Fe1+δSe)is the structurally simplest iron-based superconductor with a superconducting critical temperature(Tc)of 8.5 K at ambient pressure[2].By intercalation of alkali metal ions into
基金supported by the National Natural Science Foundation of China (Grant No. 10975066)
文摘Mossbauer spectroscopy was used to probe the site-specific information of a K0.84Fe1.99Se2 superconductor. A spin excitation gap, △E≈5.5 meV, is observed by analyzing the temperature dependence of the hyperfine magnetic field （HMF） at the iron site within the spin wave theory. Using the simple model suggested in the literature, the temperature dependence of the HMF is well reproduced, suggesting that, below room temperature, the alkali metal intercalated iron selenide superconductors can be regarded as ferromagnetically coupled spin blocks that interact with each other antiferromagnetically to form the observed checkerboard-like magnetic structure.
