Upper Critical Field and Irreversibility Line Determined by Transport Measurement of the New Superconductor MgB_(2)  

作　　者：JIN Hao WEN Hai-Hu LI Shi-Liang ZHAO Zhi-Wen NI Yong-Ming REN Zhi-An CHE Guang-Can YANG Hai-Peng LIU Zhi-Yong ZHENG Dong-Ning ZHAO Zhong-Xian 金灏;闻海虎;李世亮;赵志文;倪泳明;任治安;车广灿;杨海鹏;刘智勇;郑东宁;赵忠贤(National Laboratory for Superconductivity,Institute of Physics and Center for Condensed Matter Physics,Chinese Academy of Sciences,Beijing 100080)

机构地区：[1]National Laboratory for Superconductivity,Institute of Physics and Center for Condensed Matter Physics,Chinese Academy of Sciences,Beijing 100080

出　　处：《Chinese Physics Letters》2001年第6期823-825,共3页中国物理快报（英文版）

基　　金：Supported by the Ministry of Science and Technology of China(NKBRSF-G19990646);the National Natural Science Foundation of China under Grant No.19825111.

摘　　要：Resistive transitions of the new superconductor MgB_(2) are carried out under magnetic fields from 0 to 8 T.It is found that the irreversibility field Hirr(T)and the upper critical field Hc2(T)obtained are very close to those determined in the magnetic measurement.By using the Arrhenius activation lawρ=ρ0exp(-U/kBT),the activation barrier U has been determined by the low dissipation part of R(T)curves.It is found that U■kBT manifests a very weak thermal activation and thermal fluctuation effect.This may further indicate that the flux dynamics near Hirr(T)is induced by strong quantum fluctuation and tunneling of vortices.

关 键 词：ACTIVATION UPPER THERMAL 

分 类 号：TG1[金属学及工艺—金属学]