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SmFeAsO1-xFx超导体中的NMR和mSR

NMR and mSR in SmFeAsO1-xFx Superconductors
课程网址: http://videolectures.net/kolokviji_carretta_nmr/  
主讲教师: Pietro Carretta
开课单位: 帕维亚大学
开课时间: 2009-10-16
课程语种: 英语
中文简介:
(TC <55 K)。 将简要介绍通过19F核磁共振和SmFeAsO1-xFx超导体中的μ子自旋旋转获得的最新结果。 19F核自旋晶格弛豫,其允许探测Sm层内的低能激发,显示出具有磁性基态的重费米子化合物的相当特征的行为。 根据NMR线宽信息的温度依赖性,可以推导出磁通线晶格的静态特性和超导有序参数。 将这些结果与通过μ子自旋旋转获得的结果进行比较,这是研究伦敦穿透深度的掺杂和温度依赖性的有力工具,并证明在微观水平上超导和磁性可能共存。 在整个研讨会期间,将在铜酸盐和铁基超导体中观察到的现象学进行比较。
课程简介: Among the recently discovered pnictide superconductors the highest superconducting critical temperature has been measured for SmFeAsO1-xFx family (TC < 55 K). A brief overview on recent results obtained by means of 19F nuclear magnetic resonance and muon spin rotation in SmFeAsO1-xFx superconductors will be presented. 19F nuclear spin-lattice relaxation, which allows to probe the low-energy excitations within the Sm layers, shows a behavior which is rather characteristic of heavy-fermion compounds with a magnetic ground-state. From the temperature dependence of the NMR linewidth information on the static properties of the flux lines lattice and on the superconducting order parameter can be derived. These results are compared with the ones obtained by muon spin rotation, which represents a powerful tool to study the doping and temperature dependence of the London penetration depth and to evidence the possible coexistence of superconductivity and magnetism at the microscopic level. A comparison between the phenomenology observed in cuprates and Fe-based superconductors will be made throughout the seminar.
关 键 词: 核磁共振; 重费米子化合物; 超导有序参数
课程来源: 视频讲座网
最后编审: 2019-05-12:cjy
阅读次数: 32