Measurements and modeling of HTS shielded dielectric resonators
Measurements and modeling of HTS shielded dielectric resonators
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HTS 屏蔽介质谐振器的测量和建模
DOI：
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发表时间：
1999
影响因子：
1.8
通讯作者：
A. Porch
中科院分区：
文献类型：
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作者：
N. Parker;A. P. Kharel;J. Powell;P.A. Smith;P. D. Evans;A. Porch
我们使用紧凑的金红石介质谐振器方法，在9.6 GHz频率下，在12 K至T/sub c/温度范围内，对高质量YBa/sub 2/Cu/sub 3/O/sub 7-x/ (YBCO)薄膜的表面电阻进行了精确、可重复和无损的测量。在该频率下，使用该技术测量的高温超导表面电阻绝对值的系统误差小于10 /spl mu//spl Omega/，该技术采用两种精心选择几何形状的谐振器配置。谐振器在77 K时卸载的Q因子约为10/sup 5/，在15 K以下增加到5.10/sup 5/以上。我们使用三维电磁软件（“Superfish”）来研究铜屏蔽对金红石（TiO/sub 2/）测量的影响，以及其他使用铝酸镧（LaAlO/sub 3/）作为介电材料的影响。在后一种情况下，由于LaAlO/sub - 3/具有比金红石更低的相对介电常数，因此其场能量填充因子较小，因此在测量YBCO薄膜表面电阻时存在显著的不确定性（高达100%）。
We have performed accurate, reproducible and nondestructive measurements of the surface resistance of high quality YBa/sub 2/Cu/sub 3/O/sub 7-x/ (YBCO) thin films in the temperature range 12 K to T/sub c/ using a compact rutile dielectric resonator method at 9.6 GHz. The absolute values of the HTS surface resistance have been measured to systematic errors of less than 10 /spl mu//spl Omega/ at this frequency using this technique, which employs two resonator configurations with carefully chosen geometries. The resonators have unloaded Q factors of around 10/sup 5/ at 77 K, increasing to above 5.10/sup 5/ below 15 K. We have used three dimensional electromagnetic software ("Superfish") to study the effects of the copper shield on these rutile (TiO/sub 2/) measurements, and others using lanthanum aluminate (LaAlO/sub 3/) as the dielectric material. In the latter case, there are significant uncertainties (as large as 100%) in the measurements of the surface resistance of the YBCO films owing to the smaller field energy filling factor for LaAlO/sub 3/ since it has a lower relative permittivity than rutile.