【作者】 潘军；

【导师】 林德华； 郑东宁；

【作者基本信息】 重庆大学 ， 凝聚态物理， 2008， 硕士

【摘要】 本文的研究工作主要分为两个部分,第一部分研究了YBCO薄膜生长条件和性质,第二部分是Tl2212薄膜的制备和相关性质的研究。第一部分,由于LaAlO3基片与YBCO的晶格匹配比较好,在LaAlO3基片上生长YBCO薄膜相对比较容易,所以本文采用脉冲激光沉积法(PLD)对LaAlO3基片直接生长YBCO进行了研究。系统地摸索了不同工艺参数,如基片温度、基片与靶材的距离、激光脉冲频率、激光能量、沉积气压、薄膜厚度等对YBCO薄膜的影响,得出了沉积薄膜的最佳工艺。但是,PLD制备无可避免会造成薄膜表面有小的颗粒,且沉积的薄膜还存在厚度不均匀等问题。这些缺点将严重影响薄膜的性质和质量,如Jc,Rs等。为了提高工艺的稳定性和成品率,为超导应用研究奠定基础,本文对提高薄膜的均匀性以及薄膜两面的一致性进行了探索。第二部分,介绍了两步法制备TBCCO(Tl2212)薄膜。首先我们研究了Tl源的生长条件,找到了最佳的实验温度。其次对在大气压下、不同温度制备的薄膜进行研究,探索了最佳的实验条件。运用XRD、SEM等手段分析了制备的薄膜样品。研究表明薄膜具有较好的C轴取向,表面特征良好,具体性质指标如:Rs小于0.5 m?、临界电流密度均匀且全部在106数量级以上、超导转变温度最高108.1k等。实验结果显示,我们采用单温铊化的方法可以制备出用于微波测量的两面均匀一致的大膜。随着微电子器件市场潜力的逐渐显现,人们对超导实用化也提出了新的要求。为了采用离子注入的方法做Josephson结,进一步用相应的方法研发出SQUID器件,我们首先对用于制备微波器件的薄膜进行H2+注入,找到了最合适的剂量,为后面的工作奠定基础。更多还原

【Abstract】 This study mainly divided into two parts: the first part is the growing conditions and the characters of the YBCO thin film, the preparation and characters of Tl2212 thin film is on the second part.The first part, the substrate lattice of LaAlO3 and YBCO match well and it is relatively easy to grow YBCO thin film on LaAlO3 substrate, so this article study the directly growth of YBCO thin film on LaAlO3 substrate by the method of pulsed laser deposition (PLD). It is systems explored that the impact on YBCO thin film of different technical parameters, such as the substrate temperature, the distance between the target and the substrate, laser pulse frequency, laser energy, deposition pressure, and the film thickness, etc. and the best film of the deposition process is found.However, the thin film made by the method of PLD will inevitably cause some problem, for example the surface of small particles and sediment thickness of the film are also uneven. These shortcomings will seriously affect the characters of film, such as Jc, Rs, and so on. In order to improve the process of stability and yield and further lay the foundation for the application of superconductor, this paper explore the improvement of the uniformity of the film and the consistency of the double thin film. The second part introduced Tl2212 thin film by two-step Preparation. First of all, we study the growth conditions of Tl source and find the best experimental temperature. Then Films is prepared in the atmospheric pressure at the different temperature to explore the best experimental conditions.It is analysed that the success of the film samples by XRD, SEM, etc. The result shows that the film has good C-axis oriented, good surface characteristics, the specific characters of indicators such as: Rs less than 0.5 m ?, the uniformity of the critical current density, the number of all the 106 level and above, the highest superconductor transition temperature of 108.1 k. The specific experimental results show that we can prepared the uniform double film for the measurement of microwave by the method of single temperature.As the market potential of the microelectronics devices gradually increase, so the application of superconductor are also made new demands. In order to make Josephson junction using the method of ion implantation, and further prepared SQUID devices by the corresponding method, first we implant the film by H2+ in order to find the most appropriate dose to make a basis for the behind work.更多还原