Very high upper critical fields of F-doped Fe-based layered superconductors NdO_(0.88)F_(0.12)FeAs and CeO_(0.88)F_(0.12)FeAs  

作　　者：WU Dan, LI Zheng, SU ShaoKui, DONG Jing, LI Gang, HU WanZheng, ZHENG Ping, CHEN GenFu, LUO JianLin & WANG NanLin Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China 

出　　处：《Science China(Physics,Mechanics & Astronomy)》2008年第6期715-718,共4页中国科学：物理学、力学、天文学（英文版）

基　　金：Supported by the National Basic Research Program of China (973 Program)(Grant No. 2006CB9213001);the National Natural Science Foun-dation of China (Grant No. 10774181)

摘　　要：Using the solid state reaction method, we have synthesized the polycrystalline F-doped NdO0.88F0.12FeAs and CeO0.88F0.12FeAs with the superconducting transition temperatures at about 48 and 40 K, respectively. To obtain the upper critical field Hc2 of Nd(Ce)O0.88F0.12FeAs samples, we measured the electrical resistivity under magnetic field up to 14 T. Based on the Werthamer-Helfand-Hohenberg (WHH) rela-tion together with the Hc2(T) curves in a relatively high field, we estimated that these superconductors have a rather high upper critical field of about 115 T for Nd-based and 107 T for Ce-based samples, indicating the similarities between these ReO1-xFxFeAs (Re = rare earth element) superconductors and high Tc cuprate su-perconductors.Using the solid state reaction method, we have synthesized the polycrystalline F-doped NdO0.88F0.12FeAs and CeO0.88F0.12FeAs with the superconducting transition temperatures at about 48 and 40 K, respectively. To obtain the upper critical field Hc2 of Nd(Ce)O0.88F0.12FeAs samples, we measured the electrical resistivity under magnetic field up to 14 T. Based on the Werthamer-Helfand-Hohenberg (WHH) rela-tion together with the Hc2(T) curves in a relatively high field, we estimated that these superconductors have a rather high upper critical field of about 115 T for Nd-based and 107 T for Ce-based samples, indicating the similarities between these ReO1-xFxFeAs (Re = rare earth element) superconductors and high Tc cuprate su-perconductors.

关 键 词：UPPER CRITICAL field FE-BASED SUPERCONDUCTOR 

分 类 号：O511[理学—低温物理]