Preparation and Superconducting Properties of F-doped SmO_1-xF_xFeAs

Zhiyong Liu,Hongli Suo ,Lin Ma,Min Liu,Zhiping Wu,Zhichao Guo,Luping Han and Meiling Zhou Key Laboratory of Advanced Functional Materials,Ministry of Education,College of Materials Science and Engineering,Beijing University of Technology,Beijing 100022,China

摘 要：Here we report the fabrication and superconductivity of the iron-based arsenic oxide SmO1-xFxFeAs compound.X-ray diffraction（XRD） results prove that the lattice parameters a and c decrease systematically with increasing x in between 0<x≤0.35,but when x>0.35 the a and c increase with the decrease of x in the SmO1-xFxFeAs.The critical temperature（Tc） increases with increasing x in between 0.15≤x≤0.3,while x>0.3 the Tc decreases with the increase of x.It is found that at x=0.3 SmO0.7F0.3FeAs has the highest onset resistivity transition temperature of 55.5 K.The critical current density（Jc） value at 10 K for the obtained SmO0.7F0.3FeAs is 1.3×10 5 A/cm2（0T）.Meanwhile one can estimates Hc2（0） from the slope of the Hc2（T） curve at T =Tc（HC2 is the upper critical field）,and for the 90% normal-state resistivity（ρn） criterion（Tc=55 K）,Hc2（0） is determined to be ～253 T.

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