Enhanced critical current density in BaFe2(As0.66P0.33)2 nanocomposite superconducting films
Enhanced critical current density in BaFe2(As0.66P0.33)2 nanocomposite superconducting films
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DOI：
10.1088/1361-6668/ab0faf
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发表时间：
2019-05
影响因子：
3.6
通讯作者：
M. Miura;G. Tsuchiya;T. Harada;K. Tanabe;M. Kiuchi;T. Matsushita
中科院分区：
文献类型：
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作者：
M. Miura;G. Tsuchiya;T. Harada;K. Tanabe;M. Kiuchi;T. Matsushita
122型铁基超导体BaFe_2As_2具有高的上临界场和低的各向异性，使其在超导高场磁体中具有很好的应用前景。但是，其在高磁场下的临界电流密度（Jc）需要进一步提高。在这里，我们表明，通过控制沉积参数（较高的衬底温度和较低的生长速率）的脉冲激光沉积方法制备的薄膜，BaFe 2（As 0. 66 P 0. 33）2（Ba 122：P）矩阵的结晶度得到改善，同时保持高密度的非相干BaZrO 3（BZO）纳米粒子（NPs），一起导致显着增加的自场Jc。我们的Ba 122：P纳米复合薄膜还表现出增加的内场Jc，降低角各向异性的Jc和降低有害影响的热波动（蠕变率）在很宽的温度范围和磁场强度。即使在4 K和9 T（μ 0 H c）下，BZO NP掺杂的Ba 122：P薄膜也显示出超过2.1 MA cm-2的高内场Jc，这明显高于标准Ba 122：P薄膜和传统合金超导线。为了了解各种钉扎中心的贡献，我们应用了一个简单的模型，这是开发的铜酸盐，Ba 122：P膜与所有使用的参数通过拟合得到一组有限的实验数据（无自由参数），这样的温度，角度和字段属性在其他实验条件下，然后计算。这个简单的模型非常符合这两个非常不同的材料系统的实验结果。我们讨论了自然缺陷和BZO纳米颗粒对Jc与损伤电流密度之比的有效性。通过这项工作获得的122型铁基超导体的超导特性被认为是有前途的高场应用。
The high upper critical field and low anisotropy of the 122-type iron-based superconductor BaFe2As2 makes it promising for use in superconducting high field magnets. However, its critical current density (Jc) in high magnetic fields needs to be further improved. Here we show that for the film prepared by pulsed laser deposition method by controlling the deposition parameters (higher substrate temperature and lower growth rate), the crystallinity of BaFe2(As0.66P0.33)2 (Ba122:P) matrix is improved while maintaining a high density of incoherent BaZrO3 (BZO) nanoparticles (NPs) which together lead to significantly increased self field Jc. Our Ba122:P nanocomposite films also exhibit increased in-field Jc, reduced angular anisotropy of Jc and reduced detrimental effects of thermal fluctuations (creep rate) over a wide range of temperatures and magnetic field strength. The BZO NP doped Ba122:P films show high in-field Jc over 2.1 MA cm−2 even at 4 K and 9 T (μ0H∣∣c), which is significantly higher than that of standard Ba122:P films and conventional alloy superconducting wires. To understand the contribution of the various pinning centers, we applied a simple model, which was developed for cuprates, to Ba122:P film with all the parameters used derived by fitting to a limited set of experimental data (no free parameters) such that temperature, angle and field properties at other experimental conditions are then calculated. This simple model fits very well to the experimental results in these two very different material systems. We discuss the effectiveness of natural defect and BZO NPs on the ratio of Jc to the depairing current density. The superconducting properties for 122-type iron-based superconductors obtained through this work are considered promising for high-field applications.