LMO与LMO:MgO薄膜的溅射生长研究

发布时间：2018-02-03 22:06

  本文关键词： YBCO超导薄膜 射频磁控溅射 LMO模板层 LMO:MgO复合薄膜　出处：《电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：以YBa2Cu3O7-x(YBCO)为典型代表的第二代高温超导带材具有成本较低、载流能力高、机械强度好且可大批量生产等优点,所以YBCO超导带材在电能存储、电力传输以及强磁场等领域里面存在着非常广阔的应用。YBCO薄膜的良好生长离不开一个高质量的模板层。本论文主要沿用IBAD技术路线,以LMO薄膜作为模板层。但为了提高YBCO薄膜在磁场下的性能,尝试采用LMO:MgO复合薄膜代替LMO薄膜作为新的模板层。从生长工艺参数等入手,分别对LMO薄膜和LMO:MgO复合薄膜的生长进行了系统的研究。本论文的具体研究内容包括以下几个方面:1、射频磁控溅射LMO薄膜的生长条件研究:通过调节沉积温度、溅射功率、Ar气压等工艺条件,对LMO模板层的生长窗口进行研究。在最优化的工艺条件下,制得的LMO模板层薄膜(002)取向面外半高宽为3?,(110)面面内半高宽为5.4?,表面粗糙度为2 nm,为YBCO超导层提供了高质量的模板层。在研究过程中,还对LMO薄膜的生长机制进行了一定的分析。2、LMO薄膜的表面粗糙度对YBCO超导薄膜结构和性能的影响研究:主要研究了YBCO薄膜的结构和性能随着LMO薄膜表面粗糙度的变化情况。最后研究结果表明:随着LMO薄膜表面粗糙度从7 nm降到1.3 nm,YBCO薄膜的结构得到改善,临界电流密度也从1 MA/cm2上升到2.4 MA/cm2。3、射频磁控溅射LMO:MgO复合薄膜的生长研究:以LMO薄膜的工艺条件作为参考,进一步优化了LMO:MgO复合薄膜的生长窗口,并对LMO:MgO复合薄膜生长的情况进行了讨论。分别在单晶LAO基底和长有IBAD MgO薄膜的哈氏合金基带上生长LMO:MgO复合薄膜。最后得到了LMO与MgO两相大致分离生长的LMO:MgO复合薄膜。4、在LMO:MgO复合薄膜上生长YBCO超导薄膜。比较了两种薄膜上生长的YBCO薄膜结构、性能以及随磁场的变化情况。LMO:MgO复合薄膜上生长的YBCO薄膜与在LMO上生长的YBCO薄膜的结晶性和结构非常接近,但LMO:MgO复合薄膜的临界电流随着磁场的衰减趋势相对缓慢。
[Abstract]:YBA _ 2Cu _ 3O _ (7-x) YBCO) has the advantages of low cost, high current-carrying capacity, good mechanical strength and mass production, so the YBCO superconducting tape is stored in electric energy. In the field of electric power transmission and strong magnetic field, there is a very broad application. YBCO thin film can not grow without a high quality template layer. In order to improve the performance of YBCO films in magnetic field, LMO:MgO composite film is used as a new template layer instead of LMO film. The growth of LMO thin films and LMO:MgO composite films were studied systematically. The specific contents of this thesis include the following aspects: 1. The growth conditions of RF magnetron sputtering LMO thin films are studied by adjusting the deposition temperature, The growth window of LMO template layer was studied under the condition of sputtering power ar pressure and so on. Under the optimized process conditions, the LMO template layer film with half maximum width of 3? Is the width of the inside half of the face to be 5. 4? The surface roughness is 2 nm, which provides a high quality template layer for the YBCO superconducting layer. The influence of surface roughness of LMO thin film on the structure and properties of YBCO superconducting thin film was also studied. The structure and properties of YBCO thin film changed with the surface roughness of LMO thin film. The results show that the structure of LMO thin films is improved with the decrease of surface roughness from 7 nm to 1.3 nm. The critical current density also increased from 1 MA/cm2 to 2. 4 Ma / cm 2. 3. The growth of LMO:MgO composite films by RF magnetron sputtering was studied. The growth window of LMO:MgO composite films was further optimized by using the process conditions of LMO films as a reference. The growth of LMO:MgO composite thin films was discussed. The LMO:MgO composite films were grown on single crystal LAO substrates and on the Hultz alloy substrates with long IBAD MgO thin films, respectively. Finally, the LMO:MgO composite thin films grown roughly separately from LMO and MgO phases were obtained. YBCO superconducting thin films were grown on LMO:MgO composite films. The structure of YBCO thin films grown on two kinds of thin films was compared. The crystallinity and structure of the YBCO films grown on the LMO: MgO composite films are very close to those of the YBCO films grown on LMO, but the critical current of the LMO:MgO composite films is relatively slow with the decrease of the magnetic field.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2
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本文编号：1488472