Hybrid artificial pinning centers of elongated-nanorods and segmented-nanorods in YBa2Cu3O7 films
Hybrid artificial pinning centers of elongated-nanorods and segmented-nanorods in YBa2Cu3O7 films
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DOI：
10.1088/0953-2048/29/10/105010
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发表时间：
2016-10-01
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;Sakamoto, Nobuhiro;Matsumoto, Kaname
为了控制临界电流密度（J(c)）的各向异性，在YBa2Cu3O7薄膜中加入了细长纳米棒和分段纳米棒的混合人工钉钉中心（APCs）。采用不同含量的YBa2Cu3O7+BaSnO3靶材制备多层膜，形成了细长纳米棒和分段纳米棒。根据弹性计算，BaSnO3纳米棒之间无BaSnO3的YBa2Cu3O7区域受到高度应变，导致其沿c轴排列。在B//ab附近，纳米棒末端对涡旋扭结和直涡的钉住在较大范围内提高了J(c)。Jc的角依赖性随层厚和BSO含量的多层结构而系统变化。在保持BSO平均含量不变的情况下，J(c)依赖于层厚，说明BaSnO3的分布以及BaSnO3的平均含量对J(c)有影响。细长纳米棒和纳米棒末端的杂化钉钉效应改善了J(c)各向异性，但在现有薄膜中影响不大。应变和界面的控制有望导致J(c)的进一步改善。
To control the anisotropy of critical current density (J(c)), hybrid artificial pinning centers (APCs) of elongated-nanorods and segmented-nanorods were incorporated into YBa2Cu3O7 films. The elongated-nanorods and segmented-nanorods were formed by fabricating multilayer films using YBa2Cu3O7+BaSnO3 targets with a different BaSnO3 content. According to the elastic calculation, the BaSnO3-free YBa2Cu3O7 regions between BaSnO3 segmented-nanorods were highly strained, resulting in their alignment along the c-axis. Pinning of the vortex kinks and straight vortices by the nanorod ends improved J(c) in a wide range around B//ab. The angular dependence of Jc systematically varied with the multilayer structure of layer thickness and BSO content. J(c) depended on the layer thickness even with keeping the constant average BSO content, showing that the BaSnO3 distribution, as well as the average BaSnO3 content, affected the J(c). The hybrid pinning effect of elongated-nanorods and nanorod ends improved the J(c) anisotropy although the effect was not so large in the present films. The control of strain and interface is expected to lead to further improvement of J(c).