-
摘要YBa2CuO7(YBCO)是一种具有类钙钛矿结构的高温超导材料，超导转变温度Tc约为90K。超导时，它具有零电阻、完全抗磁性等特征，在电能传输与存储、磁悬浮等方面具有巨大的潜在应用，成为研究热点之一。32981
- 上一篇：CVD金刚石薄膜制备及其结构研究
- 下一篇：一步合成Fe2O3@FeS2、Fe2O3@FeS2@石墨烯复合材料及其电化学研究
本论文利用固相烧结法制备靶材。使用脉冲激光沉积法（PLD），在SrTiO3(STO)衬底和0.71Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 (PMNT)衬底上分别生长YBCO薄膜样品。利用XRD对其结构进行表征，利用AFM观察样品的表面形貌，利用PPMS测试样品的超导电性。
XRD结果表明所有薄膜样品均为单相YBCO，无杂相生成。AFM观察样品的表面起伏较小，为岛状生长模式。PPMS测得STO最佳生长条件为850℃，75mTorr在两种衬底上薄膜都有超导现象，Tc分别为85K和66K，说明衬底因晶格常数对薄膜产生的应变对超导转变温度有较大影响。Tc以上，所有样品均表现为金属性。
关键词 YBa2CuO7薄膜 超导 应变 脉冲激光沉积
毕业论文设计说明书外文摘要
Title Preparation of Superconducting YBCO Thin Film Grown On Ferroelectric PMNT Substrate
Abstract
YBa2CuO7 is a new type of High Temperature Superconductor(HTS) which has the defect perovskite structure and superconducting transition temperature about 90K. Unique properties like zero-resistance and diamagnetism and potential value in power transmission and storage, maglev technology make it one of hottest research spot.
In this essay, solid phase sintering was used to prepare YBCO target. The thin films were grown on SrTiO3(STO)and 0.71Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 (PMNT)substrates by pulsed laser deposition. Microstructure was characterized applying X-ray diffraction. Then, with the help of atomic force microscope, the surface morphology was observed. Finally, the electric transportation property tests were carried out on physical property measurement system.
The XRD results indicate that all the samples are single-phased. AFM shows the surface undulate slightly, proved to be Volmer-Weber mode of growing. PPMS measurements give the best deposition condition on STO :the temperature is 850℃ and oxygen pressure 75mtorr. Superconductivity is discovered in both substrates, with the transition temperature to be 85k and 66k, explaining that the strain originated from the difference in lattice parameter of these two substrates exerts influence on the superconducting property to some degree. When the temperature is above Tc, they appears to be metallic.
Keywords YBa2CuO7 Thin film Superconductivity Strain PLD
目 次
1 引言 1
1.1 超导材料简介 1
1.2 几种典型高温超导材料 2
1.3 对超导薄膜的应变调控 5
1.4 本文的研究目的以及主要研究内容 6
2 样品制备及测试方法 8
2.1实验材料及设备 8
2.2样品制备 8
2.2.1 多晶靶材的制备 8
2.2.2 薄膜样品的制备工艺 9
2.2.3 薄膜的形成和生长模式 11
2.3 表征测试方法 12
2.3.1 晶体结构分析 12
2.3.2 表面形貌分析 13
2.3.3 超导电性表征 14
3 实验结果与分析 16
3.1 薄膜的制备 16
3.2 YBCO薄膜实验数据分析 16
3.2.1 SrTiO3(001)衬底上生长的YBCO薄膜 16
3.2.2 PMN-PT(001)衬底上生长的YBCO薄膜 19
结 论 24
致 谢 25