Observation of selective surface element substitution in FeTe0.5Se0.5 superconductor thin film exposed to ambient air by synchrotron radiation spectroscopy

被引：8

作者：

Zhang, Nian ^{[1
,2
]}

Liu, Chen ^{[1
]}

Zhao, Jia-Li ^{[1
]}

Lei, Tao ^{[1
]}

Wang, Jia-Ou ^{[1
]}

Qian, Hai-Jie ^{[1
]}

Wu, Rui ^{[1
]}

Yan, Lei ^{[3
]}

Guo, Hai-Zhong ^{[3
]}

Ibrahim, Kurash ^{[1
]}

机构：

[1] Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China

[2] Chinese Acad Sci, Shanghai Inst Microsyst & Informat Technol, Shanghai 200050, Peoples R China

[3] Chinese Acad Sci, Inst Phys, Beijing 100091, Peoples R China

来源：

CHINESE PHYSICS B | 2016年 / 25卷 / 09期

基金：

中国国家自然科学基金;

关键词：

11 iron-based superconductor; oxidation mechanism in ambient air; selective surface element substitution; synchrotron radiation spectroscopy; X-RAY-ABSORPTION; PHASE-DIAGRAM; IRON; FE; CRYSTAL; SPECTRA; XPS;

D O I：

10.1088/1674-1056/25/9/097402

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

A systematic investigation of oxidation on a superconductive FeTe0.5Se0.5 thin film, which was grown on Nb-doped SrTiO3 (001) by pulsed laser deposition, has been carried out. The sample was exposed to ambient air for one month for oxidation. Macroscopically, the exposed specimen lost its superconductivity due to oxidation. The specimen was subjected to in situ synchrotron radiation photoelectron spectroscopy (PES) and x-ray absorption spectroscopy (XAS) measurements following cycles of annealing and argon ion etching treatments to unravel what happened in the electronic structure and composition after exposure to air. By the spectroscopic measurements, we found that the as-grown FeTe0.5Se0.5 superconductive thin film experienced an element selective substitution reaction. The oxidation preferentially proceeds through pumping out the Te and forming Fe-O bonds by O substitution of Te. In addition, our results certify that in situ vacuum annealing and low-energy argon ion etching methods combined with spectroscopy are suitable for depth element and valence analysis of layered structure superconductor materials.

引用

页数：6

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