Terahertz Time Domain Spectroscopy of YBCO Thin Films and Substrates
| Autor: | Wen-Fei Huang, 黃雯妃 |
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| Rok vydání: | 2004 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 92 In this thesis, we analyze the high frequency dielectric properties of LaAlO3、ＭgO、NdGaO3 and SrTiO3 substrates and YBa2Cu3O7 thin films in terahertz frequency with terahertz time domain spectroscopy and the superconductive properties of YBCO thin films such as London penetration depth. We setup the terahertz time domain spectroscopy system by the terahertz source and the electro-optic sampling system by ourself. This system which contains a cryostat and a dewater system, and the measurement can be work in different temperatures and low moisture. The YBCO thin films are deposited on LAO, MgO and NGO substrates by pulsed laser deposition, and we thin the STO substrates to 0.1mm by mechanical polishing. Meanwhile, we prove the equations from the electromagnetics and analyze the spectroscopy. We write the programs to complete the mathematic calculating procedure. Finally, we get the frequency and temperature dependent physical constants of samples, such as complex transmittance, complex index of refractions, complex dielectric constant, and complex conductivity, in terahertz radiation, and make discussions. In the YBCO thin films study, we can get the temperature dependent London penetration depth from the complex dielectric constant under the two-fluid model. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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