- 作者: 陳登銘 ; 林麗芳
- 作者服務機構: 交通大學應用化學系
- 中文摘要: A monophasic high-T/sub c/ superconductor YBa/sub 2/ Cu/sub 4/O/sub 8/ with T/sub c(onset)/ 80K and fine grain size has been synthesized under oxygen at 1 bar employing metal-ethandiol/citric acid (EG/CA) polyester complex precursors. In addition to the preparation, we report the results of infrared (IR) spectra, thermogravimetric analysis (TGA), and X-ray diffraction (XRD) relevant to preparation of the YBa/sub 2/Cu/sub 4/O/sub 8/ superconductor. The effect of temperature of preparation and precursor compositions (i.e. EG/CA molar ratio) on the purity and superconductivity of the YBa/sub 2/Cu/sub 4/ O/sub 8/ compound was investigated. The temperature dependence of resistivity and normal-state resistivity of the samples varied systematically with the EG/CA ratio in the precursors. T/sub c(onset)/ and the width of the superconducting transition for YBa/sub 2/Cu/sub 4/O/sub 8/ samples were determined to be 80K for all samples and 6-9K, respectively; the latter depended on the corresponding EG/CA ratios in the precursors. The Meissner fraction of YBa/sub 2/Cu/sub 4/O/sub 8/ samples determined from dc magnetization tests was independent of the EG/CA ratio. Polyester precursors can potentially be applied in large- scale preparation of high T/sub c/ ceramic-oxide superconductors and superconducting thin films.
- 英文摘要: --
- 中文關鍵字: Superconductor; Chemical Synthesis; Ambient Pressure; Temperature; Precursor
- 英文關鍵字: 超導體;化學合成;周圍壓力;溫度;前驅物