脉冲激光气相轰击法制备原位修饰纳米钇钡铜氧的组装及其磁性能研究

发布时间：2019-02-12 19:35

【摘要】：采用脉冲激光轰击修饰剂气氛中固体靶的新方法,轰击YBCO固体靶连续制得原位修饰nmYBCO乙醇溶胶,探索了修饰剂的选用对nmYBCO组装形貌的影响。结果表明选用不同种类的修饰剂对nmYBCO的组装形貌有显著影响,其中以邻苯二酚和2-硝基酚修饰后的自组装形貌较为特异规整,且重现性较好。采用脉冲激光轰击2-硝基酚气氛中的YBCO靶,连续制备2-硝基酚原位修饰nmYBCO乙醇溶胶,对其结构和性质进行了表征。结果发现2-硝基酚修饰后nmYBCO出现纳米棒和纳米球形颗粒的规整形貌,晶化程度变小；样品沉积在酸处理的锌片、碱处理的铝片和锌片上时都表现出纳米微粒的自组装生长,且组装形貌规整；2-硝基酚修饰后nmYBCO的紫外-可见吸收峰发生红移,在一定程度上影响了nmYBCO的电子结构。采用脉冲激光轰击邻苯二酚气氛中的YBCO靶,连续制备邻苯二酚原位修饰nmYBCO乙醇溶胶,对其结构和性质进行了表征。结果发现邻苯二酚修饰后YBCO纳米颗粒的形貌更为规整,出现蝶状或枝状的形貌；修饰后样品沉积在未处理的铝片、酸处理和碱处理的锌片上时表现出纳米微粒的自组装生长,形貌较为规整均一；修饰后样品紫外-可见吸收峰和荧光光谱吸收峰的强度有显著降低。采用脉冲激光轰击修饰剂气氛中固体靶的方法制得原位修饰的nmYBCO固体粉末,对其进行磁性测试。结果发现未修饰nmYBCO失去了超导性,并在30.00K以下发生铁磁相变；经2-硝基酚修饰的nmYBCO在低于54.35K时恢复了超导性；经邻苯二酚修饰的nmYBCO在低于56.84K也恢复了超导性,但体系中的非超导相在26.00K时发生了铁磁相变,并且随着温度的降低,非超导相的铁磁性急剧增强,最终甚至超过了临界磁场,破坏了体系的超导性,使得nmYBCO/邻苯二酚体系失去超导性。
[Abstract]:The in situ modified YBCO ethanol sol was prepared by bombarding the solid target in the atmosphere of the modifier by pulsed laser bombardment. The influence of the choice of the modifier on the morphology of the nmYBCO assembly was explored. The results showed that the morphology of nmYBCO was significantly affected by different modifiers. The self-assembly morphology of nmYBCO modified by catechol and 2-nitrophenol was more specific and regular, and its reproducibility was better. The YBCO target in 2-nitrophenol atmosphere was bombarded by pulsed laser, and 2-nitrophenol in-situ modified nmYBCO ethanol sol was prepared continuously. Its structure and properties were characterized. The results showed that the morphology of nanorods and spherical particles appeared in nmYBCO modified by 2-nitrophenol, and the degree of crystallization became smaller. The samples deposited on acid treated zinc sheet, alkali treated aluminum sheet and zinc sheet showed self-assembly growth of nano-particles, and the assembly morphology was regular. The UV-Vis absorption peak of nmYBCO modified by 2-nitrophenol is red-shifted, which influences the electronic structure of nmYBCO to some extent. The nmYBCO ethanol sol modified by catechol in situ was prepared by pulsed laser bombardment of YBCO target in catechol atmosphere. Its structure and properties were characterized. The results showed that the morphology of YBCO nanoparticles modified by catechol was more regular and sphenoid or dendritic. The modified sample deposited on the untreated aluminum sheet, acid treatment and alkali treatment of zinc showed the self-assembly growth of nanoparticles, the morphology is more uniform; The intensity of UV-visible absorption peak and fluorescence absorption peak were significantly decreased after modification. The in situ modified nmYBCO solid powder was prepared by pulsed laser bombardment of solid target in the atmosphere of modifier and its magnetic properties were tested. The results showed that the superconductivity of unmodified nmYBCO was lost and ferromagnetic phase transition occurred below 30.00K, and the superconductivity of nmYBCO modified by 2-nitrophenol was restored below 54.35 K. The superconductivity of nmYBCO modified by catechol was also restored below 56.84K, but the ferromagnetic phase transition occurred in the non-superconducting phase at 26.00K, and the ferromagnetism of the non-superconducting phase increased sharply with the decrease of temperature. Finally, the superconductivity of the nmYBCO/ catechol system is destroyed by even exceeding the critical magnetic field, which leads to the loss of superconductivity of the nmYBCO/ catechol system.
【学位授予单位】：福建师范大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TB383.1

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