Microwave characterization of normal and superconducting states of MOCVD made YBCO tapes
Microwave characterization of normal and superconducting states of MOCVD made YBCO tapes
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DOI：
10.1088/1361-6668/aa52a4
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发表时间：
2017-01
影响因子：
3.6
通讯作者：
J. Wosik;J. Krupka;Kuang Qin;Dhivya Ketharnath;E. Galstyan;V. Selvamanickam
中科院分区：
文献类型：
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作者：
J. Wosik;J. Krupka;Kuang Qin;Dhivya Ketharnath;E. Galstyan;V. Selvamanickam
我们使用了微波，非接触，非破坏性，介质谐振器（DR）技术来表征不同质量的YBCO/Hastelloy带材的复电导率的目的，探索这样的技术作为一个潜在的质量控制方法的YBCO带材的制造。使用MOCVD技术在不同温度下在哈氏合金支撑的氧化物缓冲层上沉积带。缓冲叠层由氧化铝（Al 2 O3）、氧化钇（Y2 O3）和织构化离子束辅助沉积MgO和LaMnO 3层组成。设计了两种介质谐振器（DR），即工作在13 GHz准TE 01 δ模式的高介电常数钛酸钡锆陶瓷单柱DR和工作在9.4 GHz TE 011模式的金红石单晶圆片棒DR，分别满足超导体正常态和超导态电导率表征的灵敏度要求。为了从Q因子和谐振频率偏移的实验数据计算复电导率，使用基于有限元分析的商业电磁模拟器HFSS。从微波场的全波数值模拟得到的理论Q因子和谐振频率的电导率函数与实验数据相匹配，以确定在正常和超导状态下的YBCO带材的电导率。此外，为了比较的目的，280 nm厚的高品质的YBCO外延膜沉积在介质衬底上，也进行了表征，包括频率依赖性的复电导率。通过测量YBCO/Hastelloy带材在正常状态下的电导率-温度斜率，讨论了使用DR微波技术作为质量控制工具的可行性。此外，Hastelloy基板的微波电导率值作为温度的函数的报告。
We have used a microwave, non-contact, non-destructive, dielectric resonator (DR) technique to characterize complex conductivity of different quality YBCO/Hastelloy tapes for the purpose of exploring such a technique as a potential quality control method for fabrication of YBCO tapes. The tapes were deposited at different temperatures on Hastelloy-supported oxide buffer layers using the MOCVD technique. The buffer stack consisted of aluminum oxide (Al2O3), yttrium oxide (Y2O3), and textured ion beam assisted deposition-MgO and LaMnO3 layers. Two dielectric resonators (DRs), the single post DR, consisting of high-permittivity barium zirconium titanate ceramic operating at 13 GHz in quasi-TE01δ mode, and the rod DR, consisting of rutile single crystal disk operating at 9.4 GHz in-TE011 mode, were designed to meet sensitivity requirements for characterization of conductivity of the superconductor at normal and superconducting states, respectively. For calculations of complex conductivity from experimental data of Q-factor and resonant frequency shift, a commercial electromagnetic simulator HFSS, based on finite elements analysis, was used. The theoretical Q-factor and resonant frequency on conductivity functions obtained from full wave numerical simulations of microwave fields were matched with the experimental data to determine conductivity of the YBCO tapes in both normal and superconducting states. In addition, for comparison purposes, 280 nm thick high-quality YBCO epitaxial film deposited on a dielectric substrate was also characterized, including frequency dependence of the complex conductivity. Discussion about feasibility of using DR microwave techniques as a quality control tool via measurements of conductivity versus temperature slope of the YBCO/Hastelloy tape in normal state is included. Also, microwave conductivity values of Hastelloy substrate as a function of temperature are reported.