Enhancement of critical current density using assit pinning centers in high-Tc superconducting thin films with 1D pinning centers

采用200 MeV的正离子沿着c轴方向辐照BaZrO_3/YBa_2Cu_3 O_y准多层膜，控制BaZrO_3纳米颗粒的尺寸和空间方向。当BaZrO 3纳米颗粒的尺寸较大时，未被CD捕获的磁通线，如CD之间的间隙磁通线和双扭结磁通线，可以被BaZrO 3纳米颗粒更有效地钉扎，从而在高磁场和高温下提高Jc。此外，Jc和n值之间的负相关性出现在高温下，在增加的磁场与相关的纳米颗粒的行，可能是弯曲的c轴的薄膜。这表明，混合磁通钉扎不仅依赖于一维钉扎中心和三维钉扎中心的组合，而且还依赖于三维钉扎中心的大小和空间分布。

BaZrO3/YBa2Cu3Oy quasi-multilayered films, in which the size and the spatial dirstribution of BaZrO3 nano-particles were controlled, were irradiated using 200 MeV Xe ions along the c-axis direction. When the BaZrO3 nano-particles were larger in size, the flux lines not captured by CDs, such as interstitial flux lines between CDs and double kinks of flux lines, can be pinned more effectively by the BaZrO3 nano-particles, so that the Jc enhances for high magnetic fields and high temperature. In addition, the inverse correlation between Jc and n-value appears at high temperature in increasing magnetic field for the film with correlated rows of the nano-particles which might be curved off the c-axis. These suggest that the hybrid flux pinning depends not only on the combination of one-dimensional (1D) and three-dimensional pinning centers (3D-PCs) but also on the size and the spatial distribution of the 3D-PCs.