Open AccessSuperconductivity Modulated by Binary Doping in Nd<sub>1-x</sub>Ba<sub>x</sub>FeAsO<sub>1-2x</sub>F<sub>2x</sub>
Author(s) -
Chunqing Qu,
Zhiyong Liu,
Yuming Lu,
Changzhao Chen,
Chuanbing Cai,
A. F. Fang,
Fuqiang Huang,
Mingfeng Wang,
Xiaoming Xie
Publication year - 2011
Publication title -
journal of modern physics
Language(s) - English
Resource type - Journals
eISSN - 2153-120X
pISSN - 2153-1196
DOI - 10.4236/jmp.2011.26056
Subject(s) - superconductivity , doping , electrical resistivity and conductivity , condensed matter physics , hall effect , materials science , lattice constant , analytical chemistry (journal) , physics , chemistry , diffraction , optics , quantum mechanics , chromatography
Binary doping effect is studied for the Fe-based superconductors of Nd1-xBaxFeAsO1-2xF2x(x = 0.02, 0.05, 0.1, 0.15, 0.2). The X-ray diffractions show that the c-axis lattice constant decreases monotonously with the doping content, in contrast to the little change in the a-axis. Temperature dependences of electric resistivity and magnetic susceptibility reveal that the superconductivity for the studied system emerges at x = 0.1, and enhances together with Hc2(0) as the doping content x increases further. In case of x = 0.2, the superconducting critical temperature reaches as high as 50 K, which is the first demonstration of superconductivity with a high fluorine-doping induced by both electron and hole doping in this family. Negative Hall coefficient (RH) indicates that electron-type carriers are dominated in the present samples. The complicated temperature dependence of RH, is believed to arise from a multiband effect together with a complicated scattering, especially at the tem-perature near the TC