YBa2Cu3O7-x纳米复合薄膜磁通钉扎特性的研究进展

Advances of Vortex Pinning in YBa2Cu3O7-x Nanocomposite Thin Films

自1986年发现高温超导体以来，YBa2Cu3O7-x（YBCO）超导体以其高临界温度、高不可逆场、强载流能力等优势受到了各国学者的广泛关注和研究。随着薄膜制备技术的发展，晶界弱连接问题已经不再是提升YBCO超导性能的主要障碍，限制YBCO涂层导体临界电流的主要因素是其磁通钉扎能力。为此，世界众多的科研机构开展了在YBCO薄膜中引入不同缺陷提高磁通钉扎的研究。总的来说，最常采用的钉扎策略是在YBCO母体中加入第二相纳米颗粒，形成人工钉扎中心，从而起到磁通钉扎的作用。磁通钉扎机制在以脉冲激光沉积法、化学气相沉积法等为主的原位法和以化学溶液法为主的非原位法中存在明显的差异。本文对近年来原位法和非原位法制备的复合薄膜中人工钉扎中心的影响机制以及磁通钉扎特征进行了系统的总结和阐述。

Since the discovery of high temperature superconductors in 1986, YBa2Cu3O7-x （YBCO）, with the advantages of high critical temperature, high critical magnetic field and high current-carrying capacity, has attracted much attention and researches. With the development of thin film preparation technology, the grain boundary problem which once hindered the enhancement of critical cur- rent density has been resolved. While the main factor which limited the enhancement of the critical current density was the vortex pin- ning ability of coated conductor. Thus many scientific institutions and research groups made a full research on introducing different de- fects to improve the flux pinning efficiency. In conclusion, the most commonly used strategy for flux pinning was to add a second nano- particleas artificial pinning centers in the YBCO matrix, therefore the critical current of YBCO in a high magnetic field could be better enhanced. Many studies showed that the flux pinning mechanism was different between the in situ method and ex situ method. Depen- ding on researches of recent years, this paper systematically summarized the flux pinning features of nano-composite film under this two different film preparation technologies.