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利用正电子湮没技术,结合X射线衍射和扫描电子显微镜结构分析,对Y-123超导体烧结过程进行了研究,给出了烧结时间、烧结温度对该体系结晶度和晶体结构的影响特征,发现在950℃温度烧结下,随烧结时间的增加,Y-123体系的正交畸变度增加;而就整体而言,正电子平均寿命随烧结温度和烧结时间增加而增加,并趋于饱和.证明在烧结温度为920—950℃、烧结时间为12—72h的实验条件下,Y-123超导材料中的缺陷分布趋于稳定.讨论了烧结过程中材料内部的缺陷变化特征
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关键词:
- 正电子寿命谱 /
- YBa2Cu3O7-δ超导体 /
- 烧结过程 /
- 晶体结构
Using positron annihilation,X-ray diffraction and scanning electron microscopy experiments,the structural characteristics and preparation techniques for YBa2Cu3O7-δ systems are systematically studied.The results show that,for the samples sintered at 950℃,the orthorhombic disorder increases with the duration of sintering time.On the whole,with the increase of sintering temperature and time,the positron lifetime increases until it reaches a saturation value.It is proved that,under the condition of 920—950℃ for 12—72 h,the structural characteristics and superconductivity of Y-123 have good stability.The changes of defect with the sintering temperature and time are also discussed.This experimental results indicate that the positron experiment shows good stability and reliability.-
Keywords:
- positron lifetime spectrum /
- YBa2Cu3O7-δ superconductor /
- sintering procedure /
- crystal structure
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