物理学报2001，Vol.50Issue(4)：769-774,6.
Fe掺杂YBCO体系结构变化与团簇效应的正电子实验研究
POSITRON ANNIHILATION STUDY OF THE STRUCTURE AND CLUSTERS IN Fe-DOPED YBCO
摘要
Abstract
A series of YBa2Cu3-xFexOy(x=0—0.5)samples were prepared in air by the standard solid-state-reaction method.The crystal structures and physical properties have been studied by means of positron annihilation technology (PAT), scan electronic microscope (SEM) and X-ray diffraction (XRD).Oxygen contents of the samples were determined by a volumetric method.The results of PAT show that the short lifetime component τ1 and long lifetime component τ2 are all changed anomalously between x=0.12 and 0.15 where the compounds undergo the orthorhombic-tetragonal (O-T) phase transition.In addition,the grain size of the sample with x=0.15 is much larger than that of samples with x<0.15.Based on the experimental results,we obtain the following conclusions.The positron can be used as a sensitive probe for O-T phase transition in this system.When x>0.15,the doped Fe atoms and incoming oxygens tend to associate into clusters rather than to randomly distribute over the crystal lattice.The cluster behavior is in agreement with the results of theory and other experimental results.关键词
Fe掺杂YBCO/高温超导电性/正电子湮没/结构相变分类
数理科学引用本文复制引用
刘丽华,邓冬梅,陈镇平,张金仓,董成..Fe掺杂YBCO体系结构变化与团簇效应的正电子实验研究[J].物理学报,2001,50(4):769-774,6.基金项目
国家重点基础研究专项基金(批准号：NKBRSF-G19990646)，国家自然科学基金(批准号：19874017)资助的课题. （批准号：NKBRSF-G19990646）
