Upper Critical Field and Irreversibility Line Determined by
Transport Measurement of the New Superconductor MgB2
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
National Laboratory for Superconductivity, Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080
Upper Critical Field and Irreversibility Line Determined by
Transport Measurement of the New Superconductor MgB2
Abstract： Resistive transitions of the new superconductor MgB2 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 law ρ = 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.
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. Upper Critical Field and Irreversibility Line Determined by
Transport Measurement of the New Superconductor MgB2[J]. 中国物理快报, 2001, 18(6): 823-825.
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. Upper Critical Field and Irreversibility Line Determined by
Transport Measurement of the New Superconductor MgB2. Chin. Phys. Lett., 2001, 18(6): 823-825.
2001, Vol. 18 
