Slow Vortex Creep Induced by Strong Grain Boundary Pinning in Advanced Ba122 Superconducting Tapes  

作　　者：Chiheng Dong He Huang Yanwei Ma 董持衡;黄河;马衍伟(Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering,Chinese Academy of Sciences;University of Chinese Academy of Sciences)

机构地区：[1]Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering,Chinese Academy of Sciences [2]University of Chinese Academy of Sciences

出　　处：《Chinese Physics Letters》2019年第6期61-65,共5页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China under Grant Nos 51402292 and 51677179;the International Partnership Program of the Chinese Academy of Sciences under Grant Nos GJHZ1775 and 182111KYSB20160014;the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences under Grant No NoQYZDJ-SSW-JSC026;the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDB25000000

摘　　要：We report the temperature, magnetic field and time dependences of magnetization in advanced Ba122 superconducting tapes. The sample exhibits peculiar vortex creep behavior. Below 10 K, the normalized magnetization relaxation rate S = d ln(-M)/d ln(t) shows a temperature-insensitive plateau with a value comparable to that of low-temperature superconductors, which can be explained within the framework of collective creep theory. It then enters into a second collective creep regime when the temperature increases. Interestingly, the relaxation rate below 20 K tends to reach saturation with increasing the field. However, it changes to a power law dependence on the field at a higher temperature. A vortex phase diagram composed of the collective and the plastic creep regions is shown. Benefiting from the strong grain boundary pinning, the advanced Bal22 superconducting tape has potential to be applied not only in liquid helium but also in liquid hydrogen or at temperatures accessible with cryocoolers.We report the temperature, magnetic field and time dependences of magnetization in advanced Ba122 superconducting tapes. The sample exhibits peculiar vortex creep behavior. Below 10 K, the normalized magnetization relaxation rate S = d ln(-M)/d ln(t) shows a temperature-insensitive plateau with a value comparable to that of low-temperature superconductors, which can be explained within the framework of collective creep theory. It then enters into a second collective creep regime when the temperature increases. Interestingly, the relaxation rate below 20 K tends to reach saturation with increasing the field. However, it changes to a power law dependence on the field at a higher temperature. A vortex phase diagram composed of the collective and the plastic creep regions is shown. Benefiting from the strong grain boundary pinning, the advanced Bal22 superconducting tape has potential to be applied not only in liquid helium but also in liquid hydrogen or at temperatures accessible with cryocoolers.

关 键 词：SLOW Vortex Creep INDUCED STRONG Grain Boundary PINNING Ba122 Superconducting TAPES 

分 类 号：O4[理学—物理]