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This paper systematically investigates the intermediate phases of YBa2Cu3O7-x (YBCO) film prepared by metalorganic deposition method using trifluoroacetates (TFA-MOD). According to x-ray diffraction and Raman analyses, the precursor film decomposed in a mixture of BaF2, Y2O3 and CuO after the pyrolysis process. Then these intermediate phases converted into tetragonal YBa2Cu3O6.5 at about 725°C. The influence of water vapour pressure on the YBa2Cu3O7-x film growth on LaAlO3 single-crystal substrates was also studied. The films prepared at low water vapour pressures (40-140 hPa) showed poor electrical performance due to the a-axis grain structure and impurity phases. However, the films prepared at 190 hPa exhibited the highest critical temperature of 90 K and the highest Jc of 3.8 MA/cm2, which was attributed to the formation of a purer YBCO phase and stronger biaxial texture. 相似文献
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YBa2Cu3O7-x(YBCO)膜存在“厚度效应”: 随着厚度增加, YBCO薄膜的临界电流密度下降, 尤其是YBCO薄膜的厚度超过1 μm时, 它的临界电流密度急剧下降. 本文在YBCO薄膜之间引入极薄的二氧化铈(CeO2)薄膜, 成功制备出结构为YBCO/YBCO/CeO2/YBCO的超导厚膜. 所制备的厚度为2 μm的YBCO膜临界电流密度为1.36 MA/cm2 (77 K, 自场), 其性能比相同厚度的纯YBCO膜有了较大幅度的提升. 研究表明CeO2薄膜起到了传递织构、松弛应力的作用. 相似文献
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硫化铅量子点(PbS QDs)的光氧化稳定性差是其应用于太阳能电池等领域的主要限制因素之一. 采用阳离子交换法在合成的PbS量子点表面包裹一层具有更稳定、更大禁带宽度的硫化镉(CdS)壳层, 制备出稳定的核/壳型PbS/CdS量子点; 同时, 研究了反应温度和反应时间对阳离子交换过程的影响规律. 通过透射电子显微镜和高分辨透射电子显微镜(TEM/HRTEM)、X射线衍射仪(XRD)、吸收光谱和荧光光谱考察了所制备PbS/CdS量子点的结构、光学特性和光氧化稳定性.结果表明: 阳离子交换过程中, 离子交换反应程度有限、仅发生在量子点的表面层, 但极薄的CdS壳层已能有效钝化PbS量子点的表面缺陷、显著提高其光氧化稳定性. 相似文献
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利用脉冲激光法研究了在(100)SrTiO3(STO)、(100)LaAlO3(LAO)和(100)Y-ZrO2(YSZ)衬底上外延生长LaCuO4(LCO),La1.85Sr0.15CuO4(LSCO),Nd1.85Ce0.15CuO4(NCCO)和Pr2CuO4(PCO)薄膜的工艺技术。利用X光衍射仪检测了不同条件下制备的薄膜样品结构和取向。X射线衍结果表明,在事适的制膜条件下可以在这三种衬底 相似文献
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