Origin of the emergence of higher T-c than bulk in iron chalcogenidethin films
| Autor: | Jung-Woo Lee, Myeong Jun Oh, Sanghan Lee, Jongmin Lee, Joo-Hyoung Lee, Mengchao Liu, Genda Gu, Peng Gao, Younjung Jo, Jianyi Jiang, Sehun Seo, Il-Seok Jeong, Jong-Hoon Kang, Chang-Beom Eom, Eric E. Hellstrom, Heesung Noh |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Multidisciplinary
Materials science Chalcogenide lcsh:R Analytical chemistry lcsh:Medicine 02 engineering and technology 021001 nanoscience & nanotechnology Epitaxy Rutherford backscattering spectrometry 01 natural sciences Article Pulsed laser deposition Chalcogen chemistry.chemical_compound Wavelength-dispersive X-ray spectroscopy chemistry 0103 physical sciences lcsh:Q Thin film lcsh:Science 010306 general physics 0210 nano-technology Ternary operation |
| Zdroj: | SCIENTIFIC REPORTS(7) Scientific reports, vol 7, iss 1 Scientific Reports Scientific Reports, Vol 7, Iss 1, Pp 1-8 (2017) |
| Popis: | Fabrication of epitaxial FeSexTe1−x thin films using pulsed laser deposition (PLD) enables improving their superconducting transition temperature (Tc) by more than ~40% than their bulk Tc. Intriguingly, Tc enhancement in FeSexTe1−x thin films has been observed on various substrates and with different Se content, x. To date, various mechanisms for Tc enhancement have been reported, but they remain controversial in universally explaining the Tc improvement in the FeSexTe1−x films. In this report, we demonstrate that the controversies over the mechanism of Tc enhancement are due to the abnormal changes in the chalcogen ratio (Se:Te) during the film growth and that the previously reported Tc enhancement in FeSe0.5Te0.5 thin films is caused by a remarkable increase of Se content. Although our FeSexTe1−x thin films were fabricated via PLD using a Fe0.94Se0.45Te0.55 target, the precisely measured composition indicates a Se-rich FeSexTe1−x (0.6 x 0.8) as ascertained through accurate compositional analysis by both wavelength dispersive spectroscopy (WDS) and Rutherford backscattering spectrometry (RBS). We suggest that the origin of the abnormal composition change is the difference in the thermodynamic properties of ternary FeSexTe1−x, based on first principle calculations. |
| Databáze: | OpenAIRE |
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