TY - JOUR
T1 - Boosting superconducting properties of Fe(Se, Te) via dual-oscillation phenomena induced by fluorine doping
AU - Liu, Jixing
AU - Zhang, Shengnan
AU - Li, Meng
AU - Sang, Lina
AU - Li, Zhi
AU - Cheng, Zhenxiang
AU - Zhao, Weiyao
AU - Feng, Jianqing
AU - Li, Chengshan
AU - Zhang, Pingxiang
AU - Dou, Shixue
AU - Wang, Xiaolin
AU - Zhou, Lian
N1 - Funding Information:
This research was supported by funding from the National ITER Program of China (No. 2015GB115001) and the International Cooperative Project in Shaanxi province (No. 2018kw-055). X.W. acknowledges support from the Australian Research Council (ARC) through an ARC Discovery Project (DP130102956), ARC Professorial Future Fellowship project (FT130100778) and the Taishan Scholars Program of Shandong Province. Z.L. and Z.C. acknowledge support through an ARC Discovery Project (DP170104116). J.L. is grateful to the China Scholarship Council (CSC) for providing his PhD scholarship. Prof. Huan Yang in Nanjing University gives some constructive suggestions of writing this paper.
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/5/22
Y1 - 2019/5/22
N2 - Fluorine-doped Fe(Se, Te) has been successfully synthesized using the melting method. A dual-oscillation effect was found in the F-doped sample, which combined both microstructural oscillation and chemical compositional oscillation. The microstructural oscillation could be attributed to alternate growth of tetragonal β-Fe(Se, Te) and hexagonal δ-Fe(Se, Te), which formed a pearlite-like structure and led to the enhancement of δl flux pinning due to the alternating distributed nonsuperconducting δ-Fe(Se, Te) phase. The chemical compositional oscillations in β-Fe(Se, Te) phase were because of the inhomogeneously distributed Se and Te, which changes the pinning mechanism from surface pinning in the undoped sample to Δκ pinning in the 5% F-doped one. As a result, the critical current, upper critical field, and thermally activated flux-flow activation energy of FeSe0.45Te0.5F0.05 were enhanced by 7, 2, and 3 times, respectively. Our work revealed the physical insights into F-doping resulting in high-performance Fe(Se, Te) superconductors and inspired a new approach to optimize superconductivities in iron-based superconductors through phase and element manipulations.
AB - Fluorine-doped Fe(Se, Te) has been successfully synthesized using the melting method. A dual-oscillation effect was found in the F-doped sample, which combined both microstructural oscillation and chemical compositional oscillation. The microstructural oscillation could be attributed to alternate growth of tetragonal β-Fe(Se, Te) and hexagonal δ-Fe(Se, Te), which formed a pearlite-like structure and led to the enhancement of δl flux pinning due to the alternating distributed nonsuperconducting δ-Fe(Se, Te) phase. The chemical compositional oscillations in β-Fe(Se, Te) phase were because of the inhomogeneously distributed Se and Te, which changes the pinning mechanism from surface pinning in the undoped sample to Δκ pinning in the 5% F-doped one. As a result, the critical current, upper critical field, and thermally activated flux-flow activation energy of FeSe0.45Te0.5F0.05 were enhanced by 7, 2, and 3 times, respectively. Our work revealed the physical insights into F-doping resulting in high-performance Fe(Se, Te) superconductors and inspired a new approach to optimize superconductivities in iron-based superconductors through phase and element manipulations.
KW - chemical doping
KW - Fe(Se, Te)
KW - flux pinning
KW - interface effect
KW - iron-based superconductor
KW - melting process
UR - http://www.scopus.com/inward/record.url?scp=85065875060&partnerID=8YFLogxK
U2 - 10.1021/acsami.9b02469
DO - 10.1021/acsami.9b02469
M3 - Article
C2 - 31007006
AN - SCOPUS:85065875060
SN - 1944-8244
VL - 11
SP - 18825
EP - 18832
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 20
ER -