无氟高分子辅助金属有机物沉积法制备SmBCO超导薄膜

发布时间：2018-01-23 06:05

本文关键词： SmBCO超导薄膜化学溶液沉积无氟高分子辅助临界电流密度　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文利用自主开发的无氟高分子辅助金属有机物沉积(PA-MOD)法在(001)取向的LaAlO3单晶基底上制备了SmBa2Cu307-x(SmBCO)超导薄膜。通过调节涂层溶液的合成参数制备了高性能的SmBCO超导薄膜。在SmBCO体系中引入不同种类的磁通钉扎中心提高了超导薄膜的载流能力。第一章主要结合超导材料的研究现状、种类、应用及超导薄膜简介等介绍了本论文的研究背景。其次,以实际应用和基础科研为导向提出了本论文的主要研究内容。第二章阐述了本论文的实验设计过程及超导体性能的表征手段。详细介绍了无氟高分子辅助金属有机物沉积法制备SmBCO的实验流程,包括涂层溶液的配制、涂覆方法及热处理工艺。并对薄膜的微观结构、晶体结构、磁性能和电输运性能的表征方式做了较为详细的介绍。第三章主要研究了不同涂层溶液合成参数(包括不同阳离子浓度和不同涂层溶液粘度)对SmBCO超导薄膜双轴织构、微观形貌及超导电性的影响。采用自主研发的PA-MOD法在LaAlO3基底上制备了阳离子浓度为1.35mol/L、1.15mol/L、1.0mol/L和0.8mol/L(各阳离子化学计量比仍为1：2：3)超导薄膜。结果表明,阳离子浓度为1.0mol/L的涂层溶液制备的薄膜具有良好的表面微观结构及双轴织构,较高的超导转变温度91.2K和液氮温区1 MA/cm2以上的零场临界电流密度,是制备高性能SmBCO超导薄膜最佳的涂层溶液的阳离子浓度。此外,本文采用PVB(聚乙烯醇缩丁醛)作为高分子添加剂研究了不同高分子添加量对超导薄膜的结构和性能的影响。研究结果表明,高分子PVB添加量为4%的涂层溶液制备的超导薄膜具有较好的双轴织构以及平整均匀、无裂纹的微观结构。此外,该黏度溶液制备的薄膜Tc为89.5K,65K、自场下的Jc达到1 MA/cm2以上,显示了良好的超导性能。第四章采用自主开发的杂质离子Cu位掺杂技术研究了Co3+掺杂对SmBCO超导薄膜双轴织构、微观形貌及超导电性的影响。此外,研究了在SmBCO体系中引入BaZrO3第二相粒子掺杂对薄膜结构和超导电性的影响。研究表明,Co3+掺杂虽然降低了体系的载流子浓度,使得掺杂薄膜的超导转变温度有所下降,但其在整个磁场和温度范围内具有更高的约化临界电流密度Jc/Jc(0),显示了较好的磁通钉扎特性。引入BaZrO3的SmBCO薄膜的Tc达到90.5K,并且Jc/Jc(0)在不同磁场强度和不同温度条件下都高于纯的超导薄膜,这可能是BaZrO3在薄膜中形成接近超导相干长度尺寸的颗粒或者应力形成的晶格局部畸变作为有效的磁通钉扎中心的原因。
[Abstract]:SmBa2Cu307-x (SmBa2Cu307-x) was prepared on LaAlO3 single crystal substrate oriented by fluorine-free polymer assisted metal organic deposition (PA-MOD) method. SmBCO). High performance SmBCO superconducting thin films were prepared by adjusting the synthesis parameters of the coating solution. Different flux pinning centers were introduced into the SmBCO system to improve the current carrying capacity of the superconducting films. The first chapter mainly combines the research status of superconducting materials. Kinds, applications and introduction of superconducting thin films are introduced in this paper. Secondly. The main research contents of this thesis are put forward based on practical application and basic scientific research. In chapter 2, the experimental design process and the characterization method of superconductor properties are described. The fluorine-free polymer auxiliary metals are introduced in detail. The experimental process of preparing SmBCO by mechanical deposition. Including the preparation of coating solution, coating method and heat treatment process, and the film microstructure, crystal structure. The characterization of magnetic properties and electrical transport properties is introduced in detail. In Chapter 3, the synthesis parameters of different coating solutions (including different concentration of cations and viscosity of different coating solutions) are studied. Biaxial texture of SmBCO superconducting films. The effect of micromorphology and superconductivity. The cationic concentration was 1.35 mol / L and 1.15 mol / L on LaAlO3 substrate by PA-MOD method. The superconducting films of 1.0 mol / L and 0.8 mol / L (the stoichiometric ratios of cations are still 1: 2: 3) show that. The film prepared with 1.0 mol / L cationic solution has good surface microstructure and biaxial texture. The high superconducting transition temperature of 91.2K and the zero field critical current density above 1 MA/cm2 in the liquid nitrogen temperature range. It is the best cationic concentration of coating solution for the preparation of high performance SmBCO superconducting film. In this paper, PVB (polyvinyl butyral) was used as a polymer additive to study the effect of different amount of high molecular weight on the structure and properties of superconducting films. The superconducting thin films prepared by the coating solution with high molecular PVB content of 4% have good biaxial texture, smooth and uniform microstructure without crack. The Tc of the film prepared by the viscosity solution is 89.5KN 65K, and the JC of the film prepared from the field is more than 1 MA/cm2. In chapter 4th, the biaxial textures of Co3 doped SmBCO superconducting thin films were studied by using the self-developed impurity ion Cu site doping technique. In addition, the effect of the doping of BaZrO3 second phase particles on the structure and superconductivity of SmBCO films was studied. The superconducting transition temperature of the doped thin films is decreased by Co3 doping, although the carrier concentration of the system is decreased. But it has higher reduced critical current density (JC / Jc0) in the whole magnetic field and temperature range. The results show that the magnetic flux pinning property is good. The Tc of the SmBCO film with BaZrO3 is up to 90.5 K. And JC / Jc0) is higher than pure superconducting films under different magnetic field intensity and different temperature. This may be why BaZrO3 forms particles close to superconducting coherent length in the film or local lattice distortion formed by stress as an effective flux pinning center.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2

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