Effect of Introduction of Artificial Pinning Center in YBa2Cu3Oy Thin Films to Reduce Surface Resistance
Effect of Introduction of Artificial Pinning Center in YBa2Cu3Oy Thin Films to Reduce Surface Resistance
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DOI：
10.1109/tasc.2017.2656125
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发表时间：
2017-01
影响因子：
1.8
通讯作者：
N. Takanashi;M. Kondo;H. Matsui;Y. Narita;A. Saito;K. Nakajima;S. Ohshima
中科院分区：
文献类型：
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作者：
N. Takanashi;M. Kondo;H. Matsui;Y. Narita;A. Saito;K. Nakajima;S. Ohshima
我们研究了 YBa2Cu3Oy (YBCO) 薄膜中人工钉扎中心 (APC) 对降低表面电阻 (Rs) 的影响。 APC的引入可以提高临界电流密度（Jc），因此APC有望降低YBCO薄膜的R s 。为了阐明效果，我们选择硅离子辐照和中子辐照来引入APC。将 500 keV 和 4 × 1012 ion/cm2 的 Si 离子和 1 MeV 转换的 1.34 × 1012 n/cm2 中子照射到沉积在 CeO2 缓冲的 Al2O3 基底上的厚度为 300 nm 的 YBCO 薄膜中。没有APC的YBCO薄膜的δω和δψ分别小于1.0度和小于2.0度，并且这些值在Si离子和中子辐照下没有太大变化。使用介质谐振器法测量有和没有Si离子照射和中子照射的YBCO薄膜的Rs。施加的磁场高达 5 T。在所有 YBCO 薄膜中，$R_{\rm s}^{(0)}$ 的磁场依赖性小于 $R_{\rm s}^{(90)}$ 的磁场依赖性。我们发现，在 20 K 和 5 T 条件下，Si 离子辐照和中子辐照的 YBCO 薄膜的 $R_{\rm s}^{(90)}$ 有所降低，并且 Si 离子辐照薄膜的 $R_{\rm s}^{(90)}$ 约为未辐照薄膜的 1/3。此外，所有薄膜的 $R_{\rm s}^{(0)}$随着磁场在 20 K 的增加，YBCO 薄膜有所下降。结果，我们发现在磁场下将 Si 离子照射到 YBCO 薄膜中对于降低 Rs 是有效的，并且表明该效果比之前报道的添加氧化物细颗粒更强。
We investigated the effect of artificial pinning centers (APCs) in YBa2Cu3Oy (YBCO) thin films to reduce the surface resistance (Rs). The introduction of APCs can increase the critical current density (Jc), so APCs are expected to decrease R s of YBCO thin films. To clarify the effect, we chose Si ion irradiation and neutron irradiation for introducing APCs. Si ions of 500 keV and 4 × 1012 ion/cm2 and neutrons of 1.34 × 1012 n/cm2 at 1 MeV conversion were irradiated in YBCO thin films with a thickness of 300 nm deposited on CeO2-buffered Al2O3 substrates. δω and δϕ of YBCO thin films without APC were less than 1.0 degree and less than 2.0 degrees, respectively, and these values were not changed very much by Si ion and neutron irradiations. Rs of YBCO thin films with and without Si ion irradiation and neutron irradiation was measured using a dielectric resonator method. The applied magnetic field was up to 5 T. The magnetic field dependence of $R_{\rm s}^{(0)}$ was smaller than that of $R_{\rm s}^{(90)}$ in all YBCO thin films. We found that $R_{\rm s}^{(90)}$ of Si ion irradiated and neutron irradiated YBCO thin films was reduced, and that $R_{\rm s}^{(90)}$ of Si ion irradiated thin films was about 1/3 that of unirradiated thin films at 20 K and at 5 T. In addition, $R_{\rm s}^{(0)}$ of all the YBCO thin films decreased somewhat as the magnetic field increased at 20 K. As a result, we found that the irradiation of Si ions into YBCO thin films was effective for reducing Rs under a magnetic field, and it was revealed that the effect was stronger than the addition of oxide fine particles which was previously reported.