高温超导体Bi2212在爆炸作用下的性能表征及分析

发布时间：2018-03-05 08:41

本文选题：爆炸加工方法　切入点：超导材料　出处：《中北大学》2017年硕士论文　论文类型：学位论文

【摘要】：提高高温超导材料的临界转变温度一直是材料科学领域的研究热点,而Bi_2Sr_2CaCu_2O_(8+δ)(Bi2212)超导材料由于其临界转变温度高、可塑性好、易加工成材更是得到了广泛的关注和深入研究。本文采用一种新颖的方法,将爆炸加工技术和超导研究结合起来,利用炸药爆炸瞬间产生的高温、高压作用于超导氧化物Bi2212,通过这种动态高温、高压同时加载的方式,来改变和提高Bi2212超导体的性能。对爆炸前、后的样品分别进行了制样和对比表征,得到以下结论:X-射线衍射(XRD)结果表明,爆炸加工后,原高温超导多晶粉体由Bi2212单一相转变为由Bi2212超导相和Bi_2Sr_2CuO_(6+δ)(Bi2201)半导体相组成的混合相,透射电子显微镜(TEM)表征结果进一步证实了这个结论;超导量子干涉仪磁强计(SQUID)和四探针法测电阻测量结果表明,超导临界温度Tc由爆炸前的84 K提高到了爆炸后的94 K,共提高10 K;场效应晶体管室温下的测试结果表明,爆炸前的样品只表现出金属特性,I-V曲线不随偏压有明显的变化,而爆炸后的样品则呈现出明显的n型半导体特性,且开关比可以达到5。也就是说,爆炸加工,使得高温超导体Bi2212的物性发生了明显的变化。爆炸加载Bi2212的方法为研究和调控高温超导材料提供了一种新的思路,是研究高温超导材料一种行之有效的手段,同时,也为研究其它对高温和高压敏感的材料提供了一个借鉴方法。
[Abstract]:Increasing the critical transition temperature of high temperature superconducting materials has always been a hot topic in the field of material science, while Bi_2Sr_2CaCu_2O_(8 未 / Bi2212) superconducting materials have good plasticity due to their high critical transition temperature. In this paper, a novel method is used to combine the explosive processing technology with the superconducting research to make use of the high temperature produced by the explosive explosion. High pressure acts on superconducting oxide Bi2212. The properties of Bi2212 superconductors are changed and improved by means of dynamic high temperature and high pressure loading simultaneously. The samples before and after explosion are prepared and compared. The following conclusions are obtained: (1) the results of X-ray diffraction (XRD) show that after explosive processing, the original high temperature superconducting polycrystalline powder is transformed from a single phase of Bi2212 to a mixed phase composed of Bi2212 superconducting phase and Bi_2Sr_2CuO_(6 未 ~ (2 +) Bi _ (2201) semiconductor phase. The results of transmission electron microscopy (TEM) characterization further confirm this conclusion, and the results of resistance measurement by means of a superconducting quantum interferometer magnetometer (squid) and a four-probe method show that, The superconducting critical temperature (Tc) was increased from 84 K before explosion to 94 K after explosion, a total increase of 10 K. The test results at room temperature of the FET show that the I-V curve of the sample before explosion only shows no obvious change with bias voltage. And the samples after explosion show obvious n-type semiconductor characteristics, and the switching ratio can reach 5. That is, explosive processing, The physical properties of high temperature superconductor Bi2212 have changed obviously. The method of explosive loading Bi2212 provides a new way to study and control high temperature superconducting materials, is an effective means to study high temperature superconducting materials, and at the same time, It also provides a reference method for the study of other materials sensitive to high temperature and high pressure.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM26

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