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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 superconductor, 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.
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Keywords:
- magnetic penetration depth /
- surface pinning /
- surface barrier effect /
- superconducting multilayer wires
[1] Ford P J, Saunders G A 2004 The Rise of the Superconductors (Boca Raton: CRC Press) p10
[2] Government U S 2011 High Temperature Superconductivity in Perspective (Washington, DC: Congress of the U.S.) p20
[3] Rogalla H, Kes P H 2011 100 Years of Superconductivity (Boca Raton:CRC Press/Taylor & Francis Group) p6
[4] Li W X, Li Y, Chen R H 2008 Phys. Rev. B 77 094517
[5] Matsushita T 2007 Flux Pinning in Superconductors (Berlin: Springer-Verlag ) p96
[6] Shantsev D V, Galperin Y M 1999 Phys. Rev. B 60 13112
[7] Johansen T H 1999 Phys. Rev. B 60 9690
[8] Clem J R 1994 Phys. Rev. B 50 9355
[9] Jung S G, Seong W K 2012 J. Appl. Phys. 111 053906
[10] Johansson J, Cedergren K 2009 Phys. Rev. B 79 214513
[11] Pogosov W V 2010 Phys. Rev. B 81 184517
[12] Iniotakis C, Dahm T 2008 Phys. Rev. Lett. 100 037002
[13] Zhang L, Qiao Q, Xu X B 2006 Physica C 445-448 236
[14] Vodolazov D Y, Peeters F M 2005 Phys. Rev. B 72 172508
[15] Koshelev A E, Vinokur V M 2001 Phys. Rev. B 64 134518
[16] Dorosinskii L, Bocuk H, Topal U 2001 Supercond. Sci. Technol. 14 839
[17] Gupta A, Narlikar A V 2009 Supercond. Sci. Technol. 22 125029
[18] Ye Z X, Li Q, Hu Y 2005 Appl. Phys. Lett. 87 122502
[19] Aytug T, Paranthaman M, Leonard K J 2008 J. Appl. Phys. 104 043906
[20] Haberkorn N, Maiorov B, Usov I O 2012 Phys. Rev. B 85 014522
[21] Stuart E B, Eduardo F, Steven A 2005 Phys. Rev. B 71 224512
[22] de Andrade M C, Dilley N R, Ruess F J 1994 Phys. Rev. B 57 708
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[1] Ford P J, Saunders G A 2004 The Rise of the Superconductors (Boca Raton: CRC Press) p10
[2] Government U S 2011 High Temperature Superconductivity in Perspective (Washington, DC: Congress of the U.S.) p20
[3] Rogalla H, Kes P H 2011 100 Years of Superconductivity (Boca Raton:CRC Press/Taylor & Francis Group) p6
[4] Li W X, Li Y, Chen R H 2008 Phys. Rev. B 77 094517
[5] Matsushita T 2007 Flux Pinning in Superconductors (Berlin: Springer-Verlag ) p96
[6] Shantsev D V, Galperin Y M 1999 Phys. Rev. B 60 13112
[7] Johansen T H 1999 Phys. Rev. B 60 9690
[8] Clem J R 1994 Phys. Rev. B 50 9355
[9] Jung S G, Seong W K 2012 J. Appl. Phys. 111 053906
[10] Johansson J, Cedergren K 2009 Phys. Rev. B 79 214513
[11] Pogosov W V 2010 Phys. Rev. B 81 184517
[12] Iniotakis C, Dahm T 2008 Phys. Rev. Lett. 100 037002
[13] Zhang L, Qiao Q, Xu X B 2006 Physica C 445-448 236
[14] Vodolazov D Y, Peeters F M 2005 Phys. Rev. B 72 172508
[15] Koshelev A E, Vinokur V M 2001 Phys. Rev. B 64 134518
[16] Dorosinskii L, Bocuk H, Topal U 2001 Supercond. Sci. Technol. 14 839
[17] Gupta A, Narlikar A V 2009 Supercond. Sci. Technol. 22 125029
[18] Ye Z X, Li Q, Hu Y 2005 Appl. Phys. Lett. 87 122502
[19] Aytug T, Paranthaman M, Leonard K J 2008 J. Appl. Phys. 104 043906
[20] Haberkorn N, Maiorov B, Usov I O 2012 Phys. Rev. B 85 014522
[21] Stuart E B, Eduardo F, Steven A 2005 Phys. Rev. B 71 224512
[22] de Andrade M C, Dilley N R, Ruess F J 1994 Phys. Rev. B 57 708
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