高温超导薄膜的本征表面阻抗测量
发布时间：2019-06-02 21:13
【摘要】：高温超导薄膜的应用非常广泛,利用高温超导薄膜制成的器件具有常规器件不可比拟的性能,这主要归功于高温超导薄膜具有非常低的本征表面阻抗Zs。它不仅直接反映了超导薄膜的损耗情况,同时还可以获得超导薄膜的穿透深度、超导能隙等信息,而且可以用来比较不同超导薄膜的质量优劣,因此,正确的测量高温超导薄膜的本征表面阻抗具有重要的意义。本文主要介绍通过介质谐振器法测量高温超导薄膜的本征表面阻抗。我们将两片超导薄膜分别放置在圆柱形蓝宝石介质柱的两个端面,首先通过测量谐振器TE012和TE021模式的谐振频率和品质因数获得有效表面电阻；再通过将其中一片超导薄膜升温,而谐振腔其余部分温度不变,获得此时随温度变化谐振腔的谐振频率的变化,通过计算可以获得超导薄膜随温度变化的穿透深度和本征表面阻抗。我们针对超导薄膜本征表面阻抗的测量特点,设计并搭建了一套测量系统。实现了具有防震性能的制冷机结构以及具有自平行功能的悬置样品介质谐振腔,同时确保超导薄膜与介质柱的间隔可调至10μm。此外,初步测试表明,在1.5 W@4.5 K的制冷机上,悬置样品介质谐振腔中样品台的温度可变范围为：下样品台温度为8.5 K-100 K,上样品台温度为9.5K-100 K。通过仿真我们计算了所要测量的模式的谐振频率及几何因子等参数,首先测量了铜腔的品质因数和谐振频率,来验证整个装置是否准确。然后测量了以YBCO构成的介质谐振器的TE012模和TE021模的谐振频率和品质因数,并计算了YBCO在温度约为15 K时的有效表面阻抗。
[Abstract]:HTS thin films are widely used. Devices made of HTS thin films have incomparable properties with conventional devices, which is mainly due to the very low intrinsic surface impedance Zs. of HTS thin films. It not only directly reflects the loss of superconducting thin films, but also obtains the penetration depth, superconducting energy gap and other information of superconducting thin films, and can be used to compare the quality of different superconducting thin films. Therefore, It is of great significance to correctly measure the intrinsic surface impedance of HTS thin films. In this paper, the intrinsic surface impedance of HTS thin films is measured by dielectric resonator method. Two superconducting thin films are placed on the two ends of the cylindrical sapphire dielectric column. firstly, the effective surface resistance is obtained by measuring the resonance frequency and quality factor of the resonator TE012 and TE021 modes. By heating up one of the superconducting thin films and keeping the temperature of the rest of the resonator unchanged, the variation of the resonant frequency of the resonator with the change of temperature is obtained. The penetration depth and intrinsic surface impedance of superconducting thin films with temperature can be obtained by calculation. According to the measurement characteristics of intrinsic surface impedance of superconducting thin films, a set of measurement system is designed and built. The structure of the refrigerator with shock resistance and the suspended sample dielectric resonator with self-parallel function are realized, and the interval between the superconducting film and the dielectric column can be adjusted to 10 渭 m. In addition, the preliminary test shows that on the refrigerator with 1.5 W 鈮，
本文编号：2491427
[Abstract]:HTS thin films are widely used. Devices made of HTS thin films have incomparable properties with conventional devices, which is mainly due to the very low intrinsic surface impedance Zs. of HTS thin films. It not only directly reflects the loss of superconducting thin films, but also obtains the penetration depth, superconducting energy gap and other information of superconducting thin films, and can be used to compare the quality of different superconducting thin films. Therefore, It is of great significance to correctly measure the intrinsic surface impedance of HTS thin films. In this paper, the intrinsic surface impedance of HTS thin films is measured by dielectric resonator method. Two superconducting thin films are placed on the two ends of the cylindrical sapphire dielectric column. firstly, the effective surface resistance is obtained by measuring the resonance frequency and quality factor of the resonator TE012 and TE021 modes. By heating up one of the superconducting thin films and keeping the temperature of the rest of the resonator unchanged, the variation of the resonant frequency of the resonator with the change of temperature is obtained. The penetration depth and intrinsic surface impedance of superconducting thin films with temperature can be obtained by calculation. According to the measurement characteristics of intrinsic surface impedance of superconducting thin films, a set of measurement system is designed and built. The structure of the refrigerator with shock resistance and the suspended sample dielectric resonator with self-parallel function are realized, and the interval between the superconducting film and the dielectric column can be adjusted to 10 渭 m. In addition, the preliminary test shows that on the refrigerator with 1.5 W 鈮，
本文编号：2491427
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