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| 題目 |
Unconventional superconductivity in iron-based superconductors |
| 講師 |
Prof. H.H. Wen
National Lab for Superconductivity, Institute of Physics,
Chinese Academy of Sciences |
| 日時 |
平成20年10月31日 16：00～17：30 |
| 場所 |
コラボレーション棟4F 共同研究室 |
| 要旨 |
I will talk about several results achieved in our group. Firstly I will talk about the unconventional superconductivity evidenced by low temperature specific heat,
lower critical field and point contact tunneling spectrum. I will tell the distinctions between the 1111 phase and the 122 phase.
Secondly we show the discovery and recent development in hole-doped FeAs-1111 superconducting samples. In hole doped materials (Ln1-xSrx)OFeAs
(Ln denotes for some rare earth elements), it is found that the resistivity anomaly at 150 K is weakened by Sr doping,
but the weakening is much slower and a very broad rounding occurs in the resistivity vs. temperature curve,
indicating the suppression to the AF competing order in a different way compared with the electron doped side.
Thirdly we present some recent data on single crystals. A rather small anisotropy is found for the NdFeAsOF (Tc=52 K) and Ba1-xKxFe2As2.
The intrinsic value of upper critical fields has been obtained. The normal state Hall effect clearly indicates a multiband feature in all samples.
An evaluation of applications of the iron-based superconductors will be given.
References:
- H. H. Wen et al., Europhys. Lett. 82, 17009 (2008).
- X. Zhu et al., Supercond. Sci. Tech. 2008
- G. Mu et al., Chin. Phys. Lett. 2008
- L. Shan et al., Europhys. Lett. 2008
- L. Fang et al., Condmat 0803.3978
- P. Cheng et al., Science in China G51, 719-722(2008).Condmat 0804.0835.
- C. Ren et al., Condmat 0804.1726
- Y. Jia et al., APL 2008.
- H. Yang et al., PRB 2008
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| 世話人 |
理学部物理学科 鄭 国慶 （内線：7813） |
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