摘要(英) |
By using a home-made ultrashort pulsed laser deposition system, super-conducting yttrium barium copper oxide (YBCO) thin films are fabricated. Several parameters such as pump laser energy, wavelength, substrate temperature, and oxygen density are adjusted to fine the optimal condition for the growing process. The structure and crystal orientation of the thin films are characterized by using the x-ray diffraction method, showing that polycrystalline structure is obtained. The surface quality is characterized by using a surface profiler and an optical microscopy, revealing that it is spread with micrometer-size islands. Finally, by using a laser scanning confocal microscopy to measure the reflection from the YBCO thin film, the two dimensional distribution of its critical temperature is obtained. This distribution is varied in a micrometer length scale, which consists with the results of its polycrystalline structure and surface quality.
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