Angular vortex phase diagram in YB2Cu3O7 films with c-axis correlated pinning centers
Angular vortex phase diagram in YB2Cu3O7 films with c-axis correlated pinning centers
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具有 c 轴相关钉扎中心的 YB2Cu3O7 薄膜中的角涡旋相图
DOI：
10.1088/1361-6668/ac0953
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发表时间：
2021
影响因子：
3.6
通讯作者：
Matsumoto Kaname
中科院分区：
文献类型：
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作者：
Horide Tomoya;Ichino Yusuke;Matsumoto Kaname
高温超导体（HTSCs）在纳米尺度钉钉中心的影响下表现出丰富的涡旋相，各向异性的涡旋钉钉、涡旋相互作用和线张力实现了涡旋的复杂构型和行为。为了了解涡旋的行为和结构，制备了含有自组织纳米棒（basno3、BaZrO 3、BaHfO 3）的YBa 2 Cu 3 O 7薄膜，并在65 ~ 90 K温度下测量了纳米棒（//c轴）与磁场（θ）夹角变化时的临界电流密度和电阻率。强纳米棒的俘获角（θ ts）决定了在低于匹配场（B< B φ）的磁场中涡流相位边界。由于纳米棒上的涡流调节作用，θ< θ ts具有较大的c轴J c峰和电阻率下降，而θ> θ ts的涡流是由基体不相关缺陷和/或ab面钉住中心钉住的。在高于B φ (B b> B φ)的磁场中，弱矩阵c轴相关缺陷（如孪晶界）在小于矩阵c轴相关缺陷捕获角的角度处容纳涡流。虽然矩阵c轴相关缺陷在较大角度下不会固定矩阵涡，但由于磁场倾斜而出现的空纳米棒部分会固定矩阵涡。这种涡流重陷导致离轴J c峰和离轴电阻率倾角。因此，基体缺陷的弱钉钉、笼形电位、涡旋重陷以及纳米棒的强钉钉决定了含有c轴相关钉钉中心的HTSCs的角涡相位。
High temperature superconductors (HTSCs) exhibit rich vortex phases under the influence of nanoscale pinning centers, and complicated configurations and behavior of vortices are realized by anisotropic vortex pinning, vortex interaction, and line tension. To understand the behavior and configurations of vortices, YBa 2 Cu 3 O 7 films containing self-organized nanorods (BaSnO 3, BaZrO 3, BaHfO 3) were prepared, and the critical current density and the resistivity were measured for varying angles between the nanorods (//c-axis) and the magnetic field (θ) in the temperatures of 65–90 K. The trapping angle of the strong nanorod (θ ts) determines the vortex phase boundary in the magnetic field lower than the matching field (B< B ϕ). While the large c-axis J c peak and the resistivity dip are observed for θ< θ ts due to the vortex accommodation on the nanorods, the vortices for θ> θ ts are pinned by the matrix uncorrelated defects and/or the ab-plane pinning centers. In the magnetic field higher than B ϕ (B> B ϕ), the weak matrix c-axis correlated defects such as twin boundaries accommodate vortices at the angles smaller than the trapping angle of the matrix c-axis correlated defect. Although the matrix c-axis correlated defects do not pin the matrix-vortices for the larger angles, the matrix-vortices are pinned by the vacant nanorod portions that appear due to the magnetic field tilt. This vortex retrapping results in the off-axis J c peak and the off-axis resistivity dip. Thus, the weak pinning by matrix defects, the cage potential, and the vortex retrapping as well as the strong nanorod pinning determine the angular vortex phase of the HTSCs containing c-axis correlated pinning centers.