Effects of Te- and Fe-doping on the superconducting properties in FeySe1-xTex thin films

Yalin Zhang; Tong Wang; Zhihe Wang; Zhongwen Xing

doi:10.1038/s41598-021-04403-4

Effects of Te- and Fe-doping on the superconducting properties in Fe_ySe_1-_xTe_x thin films

Sci Rep. 2022 Jan 10;12(1):391. doi: 10.1038/s41598-021-04403-4.

Authors

Yalin Zhang^{1

2}, Tong Wang³, Zhihe Wang^{4

5}, Zhongwen Xing^{6

7}

Affiliations

¹ National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
² College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, China.
³ Department of Mathematics, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
⁴ National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China. zhwang@nju.edu.cn.
⁵ School of Physics, Nanjing University, Nanjing, 210093, China. zhwang@nju.edu.cn.
⁶ National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China. zwxing@nju.edu.cn.
⁷ School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, China. zwxing@nju.edu.cn.

Abstract

High quality Fe_ySe_1-xTe_x epitaxial thin films have been fabricated on TiO₂-buffered SrTiO₃ substrates by pulsed laser deposition technology. There is a significant composition deviation between the nominal target and the thin film. Te doping can affect the Se/Te ratio and Fe content in chemical composition. The superconducting transition temperature T_c is closely related to the chemical composition. Fe vacancies are beneficial for the Fe_ySe_1-xTe_x films to exhibit the higher T_c. A 3D phase diagram is given that the optimize range is x = 0.13-0.15 and y = 0.73-0.78 for Fe_ySe_1-xTe_x films. The anisotropic, effective pining energy, and critical current density for the Fe_0.72Se_0.94Te_0.06, Fe_0.76Se_0.87Te_0.13 and Fe_0.91Se_0.77Te_0.23 films were studied in detail. The scanning transmission electron microscopy images display a regular atomic arrangement at the interfacial structure.

Abstract

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