Bi_(1.8)Pb_(0.4)Sr_2Ca_(2.2)Cu_3O_y的磁通运动与临界电流特征  

FLUX MOTION AND CRITICAL CURRENT CHARACTERISTICS OF Ag-SHEATHED Bi_(1.8)Pb_(0. 4)Sr_2Ca_(2.2)Cu_3Oy TAPES

作　　者：曾朝阳[1] 史可信[1] 余正[1] 丁世英[1] 周贻茹[2] 叶兵 

机构地区：[1]南京大学物理系固体微结构物理国家重点实验室,南京210008 [2]北京有色金属研究总院,北京100088

出　　处：《物理学报》1993年第7期1160-1166,共7页Acta Physica Sinica

基　　金：国家超导技术联合研究开发中心资助的课题

摘　　要：制备了银包套的Bi_(1.8)Pb_(0.4)Sr_2Ca_(2.2)Cu_3O_y带材。微结构观察证明样品是高度织构化的Bi2223单相。输运测量发现J_c(T,B,θ,φ)和 R(T,B,θ,φ)均与θ有关,与φ无关(T=77K,B<1T),式中的θ和φ分别表示磁场与ab面和电流的夹角。求得了磁通运动的激活能。提出了热激活磁通弯结的形成与运动模型,并用London理论计算了弯结的形成能,它和实验求得的激活能一致,使本模型基本上解释了实验结果。还讨论了提高这种材料临界电流的方法。Ag-sheathed Bi(1.8)Pb(0.4)Sr2Ca(0.2)Cu3Oy superconducting tapes were prepared. Microstruc-ture examination shows that it were made of highly textured Bi2223 single phase. Measurements of transport properties in liquid nitrogen and field lower than 1T reveal that J_c(T,B,θ, φ) and R(T,B,θ,φ) of this material are θ dependent and φ independent, where θ is the angle between magnetic field and ab plane and φ is the angle between magnetic field and transport current. Activation energy of flux lines was gained. The Arrhenius relation of R(T,B) was observed and activation energy of flux motion was determined. The transport characteristics and the activation energy are explained as the thermally activated flux line diffusive motion over intrinsic flux pinning barrier by means of nucleation of two-dimensional pancake vortex pairs.

关 键 词：超导体 铋系 磁通钉扎 临界电流 

分 类 号：O511.1[理学—低温物理]