Title

Boosting Superconducting Properties of Fe(Se, Te) via Dual-Oscillation Phenomena Induced by Fluorine Doping

RIS ID

135879

Publication Details

Liu, J., Zhang, S., Li, M., Sang, L., Li, Z., Cheng, Z., Zhao, W., Feng, J., Li, C., Zhang, P., Dou, S., Wang, X. & Zhou, L. (2019). Boosting Superconducting Properties of Fe(Se, Te) via Dual-Oscillation Phenomena Induced by Fluorine Doping. ACS Applied Materials and Interfaces, 11 18825-18832.

Abstract

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 κ pinning in the 5% F-doped one. As a result, the critical current, upper critical field, and thermally activated flux-flow activation energy of FeSe 0.45 Te 0.5 F 0.05 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.

Grant Number

ARC/FT130100778, ARC/DP130102956

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