Orientation control of grain boundaries in high-temperature superconductors and elucidation of the superconductive curret flowing mechanism, The development of high-temperature superconductor tapes by the biaxial texturing using the cube textured Ni subst

高温超导体中晶界的取向控制和超导电流流动机制的阐明，使用立方织构镍基体的双轴织构开发高温超导带

基本信息

批准号：
15360333
负责人：
MATSUMOTO Kaname
金额：
$ 8.26万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

YBa_2Cu_3O_x(YBCO) has long been considered a promising candidate for next superconducting conductors operated at 77K. Trial of YBCO tape manufacture is widely carried out, to utilize high performance of the YBCO material, by using the highly textured oxide buffer layer on the metal substrates. Since the crystal anisotropy is large and the coherence length is short for YBCO, the effect of the grain boundary is remarkable. The polycrystalline substance usually is used for making the long length tape so that the suppression of J_c in the grain boundary becomes big problem. It is indispensable to develop the biaxial orientation technology which levels the grain boundary angle of YBCO films on the metal substrates in 10 degree or less for utilizing the high performance of YBCO maximally.In order to solve this issue, we have fabricated biaxial textured Ni and Ni-Cr tapes, and crystal orientation and microstructure of CeO_2 films deposited on the tapes by pulsed laser deposition were investi … More gated. Recrystallized Ni-Cr tapes had a cube texture, {l00}<001> orientation, and the surface of the tapes was occupied by the (100) preferred orientation and the strong in-plane alignment. Although recrystallized Ni tapes exhibited the {100}<001> texture and the CeO_2 films subsequently deposited on the tapes also have (100) orientation, the preferred orientation of CeO_2 films was affected by the oxygen partial pressure during pulsed laser deposition and the degree of the (100) orientation pf CeO_2 films was improved with increase of the film thickness. Moreover, we measured the magnetic field angular dependence of J_c and studied the flux pinning properties of YBCO films. We confirmed that the substrate materials and deposition temperatures have influences on the introduction of the crystalline defects into YBCO thin films, resulting in the different field angular dependence of J_c. The result shows that the dislocation perpendicularly formed in the substrate gives large effect in J_c. In this way, the possibility of controlling J_c was obtained by introduction of the high density dislocation into YBCO films on the metal substrates. Less

YBa_2Cu_3O_x(YBCO) 长期以来一直被认为是下一代在 77K 下运行的超导导体的有希望的候选者，通过在金属基底上使用高度织构化的氧化物缓冲层，广泛进行了 YBCO 带制造的试验，以利用 YBCO 材料的高性能。由于YBCO的晶体各向异性较大，相干长度较短，因此晶界的影响通常是显着的。用于制造长长度带，因此晶界J_c的抑制成为一个大问题，因此必须开发双轴取向技术，将金属基底上的YBCO薄膜的晶界角平整到10度或更小，以供使用。为了解决这个问题，我们制备了双轴织构化的Ni和Ni-Cr带材，并通过脉冲激光沉积在带材上沉积了CeO_2薄膜的晶体取向和微观结构。研究表明，再结晶镍铬带具有立方体织构、{l00}<001>取向，并且带的表面被(100)择优取向和强面内取向占据。带材表现出{100}<001>织构，随后沉积在带材上的CeO_2薄膜也具有(100)取向，CeO_2薄膜的择优取向受到以下因素的影响脉冲激光沉积过程中的氧分压和pf CeO_2薄膜的(100)取向程度随着薄膜厚度的增加而提高。此外,我们还测量了J_c的磁场角度依赖性并研究了YBCO薄膜的通量钉扎特性。我们证实衬底材料和沉积温度对YBCO薄膜中晶体缺陷的引入有影响，导致J_c具有不同的场角依赖性。结果表明，位错垂直于YBCO薄膜。基体中形成的YBCO对J_c影响较大，通过在金属基体上引入高密度位错，可以实现对J_c的控制。