Thorium-dopinginduced superconductivity up to 56 K in Gd1-xThxFeAsOCao Wang, Linjun Li, Shun Chi, Zengwei Zhu, Zhi Ren, Yuke Li, Yuetao Wang, Xiao Lin, Yongkang Luo, Shuai Jiang, Xiangfan Xu, Guanghan Cao and Zhu'an Xu
Department of Physics, Zhejiang University - Hangzhou 310027, People's Republic of China
received 26 June 2008; accepted in final form 30 July 2008; published September 2008
published online 9 September 2008
We report a new strategy to induce superconductivity in iron-based oxyarsenide. Instead of F- substitution for O2-, we employed Th4+ doping in GdFeAsO with the consideration of “lattice match" between Gd2O2 layers and Fe2As2 ones. As a result, superconductivity with Tconset as high as 56 K was realized in a Gd0.8Th0.2FeAsO polycrystalline sample. This Tc value is among the highest ever discovered in the iron-based oxypnictides.
74.70.Dd - Ternary, quaternary, and multinary compounds (including Chevrel phases, borocarbides, etc.).
74.62.Dh - Effects of crystal defects, doping and substitution.
74.62.Bf - Effects of material synthesis, crystal structure, and chemical composition.
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