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摘要摘要1987 年（Y-Ba-Cu-O）体系高温超导体被发现，其超导温度超过了液氮的温度。人们对其进行了广泛的研究，该材料已经被应用在超导电缆、超导发电机和超导量子干涉器件，在能源和国防等领域都得到了重要的应用。本文利用了自组装的超导测试系统对YBa2Cu3O7-SrRuO3薄膜进行了超导测试。具体内容如下：首先研究了薄膜的光响应性质。用氦压缩机将样品降温后，在不同温度下对样品分别施加不同频率和强度的光辐射脉冲，同时由外接的电学测量系统测量相应电阻的变化。结果表明样品电阻能受到光辐射的调控。其次研究了光辐射对超导临界温度的影响。测试降温过程中样品电阻在黑暗和光辐射条件下随温度的变化，获得相应电阻温度曲线。对比两者曲线后发现光辐射能一定地降低超导临界温度。此外本文还介绍了自制的霍尔效应测试系统以及以 p 型砷化镓基片为例进行了相应的测量。41661
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毕业论文关键词 超导体 光辐射 临界温度 霍尔效应
Title Modulation of the superconductivity of oxide superconductor andsemiconductor transport characteristics under light radiation
Abstract High temperature superconducting material(Y-Ba-Cu-O) was discovered in 1987, whosesuperconducting critical temperature exceeded the temperature of liquid nitrogen. It has beenextensively researched and has been applied to superconducting cables, superconductinggenerators and superconducting quantum interference devices, which plays an important role inthe field of energy and national defense.In this work, YBa2Cu3O7-SrRuO3 thin films were tested by self-assembly superconductivity testsystem. Details are as follows:Firstly, the light response property of the thin film was studied. The thin film was cooled byhelium compressor, and was exposed to optical radiation pulses with different frequency andintensity, at different temperature. At the same time, the changes of resistance in the film atdifferent testing conditions was measured by external electrical property measurement system.The result implies that the resistance of sample can be modulated by light radiation.Then we studied the influence of light radiation on the superconducting critical temperature. Theresistance of the film during the cooling process was tested in dark and light respectively, as aresult, two different resistance-temperature characteristic curve were obtained.. After comparingthe two curves, it indicates that a certain light radiation can reduce the superconducting criticaltemperature. In addition, the self-assembly Hall effect measurement system was introduced in this paper, anda p-type gallium arsenide substrate was measured.
Keywords superconductor light radiation critical temperature Hall effect
目 次
1 引言1
1.1 超导材料简介 1
1.1.1 超导材料发展历史. 1
1.1.2 超导材料基本特性. 2
1.1.3 BCS 理论.3
1.2 高温超导材料应用4
1.3 YBa2Cu3O7高温超导材料 5
1.4 霍尔效应概述 7
1.5 研究内容及意义 7
2 样品制备及实验研究方法和原理. 9
2.1 薄膜制备方法 9
2.1.1 磁控溅射法..9
2.1.2 溶胶凝胶法..9
2.1.3 脉冲激光沉积法..9
2.2 四引线法...10
2.3 范德堡法及霍尔效应测试系统.11
3 超导薄膜低温测试及霍尔效应测试...13
3.1 超导实验...13
3.1.1 四引线法所需电极制备...13
3.1.2 低温测试系统组装... 13
3.1.3 实验准备及样品台与薄膜样品导热性测试. 14
3.1.4 薄膜光响应研究15
3.1.5 光辐射对超导临界温度的影响.. 18
3.1.6 误差分析 22
3.2霍尔效应测试过程.23
4 结论与展望.27
4.1 结论... 27
4.2 展望... 27
致 谢28
参考文献29
1 引言随着世界经济社会的发展，人们对电能的需求越来越高。然而，很大一部分电力能源却被浪费在输电电缆上，据统计，用铝或铜制成的导线传输电力，损耗可达 15%，造成了能源的极大浪费。而用超导材料制成的输电电缆几乎不会损耗任何电能。此外，超导材料在电力领域的应用还有超导限流器、超导发电机和超导储能等等。从 1911年首次发现汞的超导电性以来， 超导材料经历了从低温超导材料到高温超导材料的转变（以液氮温度 77K为分界线）。由于低温超导材料需要使用昂贵的液氦制冷机，而高温超导材料只需价格为液氦制冷机 1/50的液氮制冷机，因此高温超导材料也就有着更广泛的应用，对其研究也更加火热。