超导线的表面区域处理提高其磁场下的输运能力  

The enhancement of current in superconductor wires by modifying and changing the surface region microstructure

作　　者：郭志超[1] 索红莉[1] 

机构地区：[1]北京工业大学材料学院,国家教育部功能材料重点实验室,北京100124

出　　处：《物理学报》2012年第23期428-432,共5页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2006CB601005);国家高技术研究发展计划(批准号:2009AA032401);国家自然科学基金(批准号:50771003;50802004);北京市自然科学基金(批准号:2092006)资助的课题~~

摘　　要：对超导体在外磁场中的特性进行了归纳,外磁场在超导体中有磁场穿透深度限制,超导体表面有超导壁垒效应和表面钉扎作用,造成了外磁场在超导线表层密度最大而芯部没有磁通穿过.表面钉扎和壁垒效应存在的竞争主要集中在表面刺入超导体的柱形空穴.为了提高超导线在外电场中的输运能力,在制备上常用提高钉扎性能,而这也有阻碍电流的作用,对超导线芯部区域没有提高钉扎作用的必要,反而因为它有害于电流传输.根据这些理论尝试设计出多层结构的超导线,内芯是致密的净超导体晶体结构,外面是与磁场穿透深度厚度相同的一层掺杂、取代等作用提高钉扎性能的外场渗透层,在超导材料表面与包套材料之间是纳米修饰或者其他手段提高表面钉扎能力的连接层,减少连接层的垂直超导线的柱形纳米空穴可提高壁垒效应.这种结构因为减少了常规制备中不考虑内部没有磁通而仍然有钉扎处理材料对载流子的散射作用,这种结构使超导线的输运能力得到了一定提高.The electromagnetic characteristics of superconductor are briefly analyzed and described, when a magnetic field is applied to the superconductor, flux lines penetrate it from the surface. The flux lines are pinned by pinning centers on the surface of the superconduc- tor, and cannot penetrate deeply from the surface and the density of the flux lines will be higher near the surface and lower in the inner region, with the participation of surface barrier effect and Meissner effect, which indicates the enhancement of pining in the core of the superconducting wire is useless and blocks the transport current. Based on this knowledge, the new multilayer structure wire is design, and the core of the wire is the high-density superconductor crystal covered by doping or changing microstructure layer with thickness as the penetration depth, outer part of the superconducting region is modified, by nanoparticle surface decorating, electron and heavy ion irradiation and extension to surface. Furthermore the Columnar defects, located near the surface, which suppress the surface barrier but create gigantic surface pinning, and the other pining centers have not this property. Then the superconducting region is wrapt by the normal metal.

关 键 词：磁场穿透深度 表面钉扎 壁垒效应 多层结构超导线 

分 类 号：TM26[一般工业技术—材料科学与工程]