Enhancing magnetic pinning by BaZrO 3 nanorods forming coherent interface by strain-directed Ca-doping in YBa 2 Cu 3 O 7−x nanocomposite films
Enhancing magnetic pinning by BaZrO 3 nanorods forming coherent interface by strain-directed Ca-doping in YBa 2 Cu 3 O 7−x nanocomposite films
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通过在 YBa 2 Cu 3 O 7-x 纳米复合薄膜中通过应变定向 Ca 掺杂形成相干界面来增强 BaZrO 3 纳米棒的磁钉扎
DOI：
10.1088/1361-6668/ac1fd3
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发表时间：
2021
影响因子：
3.6
通讯作者：
Wu, Judy
中科院分区：
文献类型：
--
作者：
Ogunjimi, Victor;Sebastian, Mary Ann;Zhang, Di;Gautam, Bibek;Jian, Jie;Huang, Jijie;Zhang, Yifan;Haugan, Timothy;Wang, Haiyan;Wu, Judy
采用沿 YBa 2 Cu 3 O 7 (YBCO) c 轴排列的 BaZrO 3 (BZO) 一维人工钉扎中心 (1D-APC) 来增强 BZO/YBCO 纳米复合材料薄膜中的磁涡钉扎。然而，BZO 1D-APCs 的钉扎力密度 F p 在接近 77 K 的温度下保持适中。主要限制因素的假设是 BZO 1D-APCs/YBCO 界面缺陷，这是源自 BZO/YBCO 晶格失配约 7.7% 的大界面应变的直接结果。在此，我们探索动态扩大 YBCO 的 c 轴以减少晶格失配，从而防止形成有缺陷的 BZO 1D-APCs/YBCO 界面。具体来说，c轴扩大是通过使用应变定向Ca扩散到YBCO中来实现的，其中两个厚度仅10 nm的Ca 0.3 Y 0.7 Ba 2 Cu 3 O 7− x (CaY-123)间隔物插入总厚度约150 nm的2 vol% BZO 1D-APC/YBCO纳米复合薄膜中，用Ca部分取代YBCO晶格上的Cu，从而实现c轴扩大。所实现的拉长 c 轴归因于 YBCO 晶格上 Ca 取代 Cu 引起的堆垛层错的形成。减少的 BZO/YBCO 晶格失配允许形成缺陷可忽略不计的相干 BZO 1D-APC/YBCO 界面。这导致在 65 K 时 F p 值高达 98 GN m− 3，比参考 2 vol% BZO 1D-APC/YBCO 样品高 70%。此外，具有与 YBCO 相干界面的 BZO 1D-APC 增强钉扎的优势可以扩展到磁场方向的大角度范围。这项研究揭示了 BZO/YBCO 界面对 BZO 1D-APC 钉扎效率的显着影响，并为在 BZO/YBCO 纳米复合材料薄膜中实现相干界面提供了一种有前景的方法。
BaZrO 3 (BZO) one-dimensional artificial pinning centers (1D-APCs) aligned along the c-axis of the YBa 2 Cu 3 O 7 (YBCO) have been adopted to enhance the magnetic vortex pinning in BZO/YBCO nanocomposite films. However, the pinning force density F p of the BZO 1D-APCs remains moderate at temperatures near 77 K. A hypothesis of the major limiting factor is the defective BZO 1D-APCs/YBCO interface as a direct consequence of the large interfacial strain originated from the BZO/YBCO lattice mismatch of∼ 7.7%. Herein, we explore enlarging the c-axis of the YBCO dynamically to reduce the lattice mismatch and hence to prevent formation of the defective BZO 1D-APCs/YBCO interface. Specifically, the c-axis enlargement was achieved by partial replacement of Cu with Ca on the YBCO lattice using strain-directed Ca diffusion into YBCO from two Ca 0.3 Y 0.7 Ba 2 Cu 3 O 7− x (CaY-123) spacers of only 10 nm in thickness inserted into the 2 vol% BZO 1D-APC/YBCO nanocomposite thin films of∼ 150 nm in total thickness. The achieved elongated c-axis is attributed to the formation of stacking faults induced by Ca-replacement of Cu on YBCO lattice. The reduced BZO/YBCO lattice mismatch allows formation of a coherent BZO 1D-APC/YBCO interface with negligible defects. This leads to an enhanced F p value up to 98 GN m− 3 at 65 K, which is 70% higher than that of the reference 2 vol% BZO 1D-APC/YBCO sample. Furthermore, the benefit of the enhanced pinning of the BZO 1D-APCs with a coherent interface with YBCO can be extended to a large angular range of the magnetic field orientation. This study reveals the significant effect of the BZO/YBCO interface on the pinning efficiency of BZO 1D-APCs and provides a promising approach to achieve a coherent interface in BZO/YBCO nanocomposite films.