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

Zhang, Yalin; Wang, Tong; Wang, Zhihe; Xing, Zhongwen

doi:10.1038/s41598-021-04403-4

Cited by 16 publications

(13 citation statements)

References 43 publications

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“…All the films have a thickness of 330 nm. The presence of volatile Se and Te elements can cause the composition of the FeSeTe thin films to be inconsistent with that of the targets [24], and such compositional inconsistency varies with the substrate temperature due to the re-evaporation of film components from the substrate [25][26][27]. Therefore, in this work, the deposition temperature was tuned in the range of 350 • C-500 • C to obtain a series of Fe y Se x Te 1−x thin films with different compositions.…”

Section: Methodsmentioning

confidence: 99%

“…Although crystalline lattice behaving instable for bulk materials, tetragonal phase can be stabilized utilizing the compressive stress from the substrate for FeSeTe films with Fe deficiency. It has been reported that FeSeTe superconductor still exhibits high T c at Fe content of 0.8 or less [11,14,24]. However, systematic study of the Fe dependence on superconductivity is still lacking.…”

Section: Introductionmentioning

confidence: 99%

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Reassembled phase diagram for Fe_ySe_xTe_1−x superconducting films grown by pulsed laser deposition

Zhang,

He,

Xiao

et al. 2023

Supercond. Sci. Technol.

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FeySexTe1−x targets with different Fe contents have been prepared by the solid state reaction method followed by the hot-pressed sintering, and corresponding single-phase FeySexTe1−x films with high quality have been deposited at different substrate temperatures by the pulsed laser deposition. The evolution of the structure, superconductivity and pinning mechanism of the FeySexTe1−x superconductors with the Fe content has been investigated in detail. It can be found that the excess Fe can form the residual Fe impurities scattered in the polycrystalline bulks when the Fe content in the nominal composition exceeds 1.36. More importantly, a reassembled phase diagram for FeySexTe1−x superconducting films based on the change of both Fe and Se contents is constructed for the first time. It can be clearly seen that both the Fe and Se contents can greatly affect the superconductivity of FeySexTe1−x films within a wide range of Fe content (0.67 ≤ y ≤ 1.48). The Fe vacancies caused by the Fe deficiency is beneficial to the improvement of both critical temperature and activation energy, while with the increase of the Fe content, the superconductivity degrades because of the introduction of the interstitial Fe and the planar defects. The optimal Fe content at constant Se content shifts to the higher value with the increase of Se content. Our results facilitate the rational regulation of the superconducting properties, as well as the study of the underlying superconducting mechanism of FeSeTe superconductors.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reassembled phase diagram for Fe_ySe_xTe_1−x superconducting films grown by pulsed laser deposition

Zhang,

He,

Xiao

et al. 2023

Supercond. Sci. Technol.

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“…It is worth noting that a deviation in the chemical composition between the nominal target and the final films was consistently observed in FST thin films produced by PLD . This phenomenon is likely due to differences in the transfer and growth rates of Fe, Se, and Te elements during the deposition process …”

Section: Resultsmentioning

confidence: 92%

“…48 This phenomenon is likely due to differences in the transfer and growth rates of Fe, Se, and Te elements during the deposition process. 49 TEM was utilized to investigate the microstructure and superconducting properties of the FST thin films, with a particular focus on 200 nm-(Figure 3a,b) and 1 μm-thick films (Figure 3c,d). In Figure 3a, the LMO buffer layer showed different white and black columnar contrast, indicating different types of grains.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Critical Role Played by Interface Engineering in Weakening Thickness Dependence of Superconducting and Structural Properties of FeSe_0.5Te_0.5-Coated Conductors

Song

Xiong³

et al. 2023

ACS Appl. Mater. Interfaces

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Increasing the thickness of a superconducting layer and simultaneously reducing the thickness effect in iron-based superconducting coated conductors are particularly essential for improving the critical current I c . Here, for the first time, we have deposited high-performance FeSe 0.5 Te 0.5 (FST) superconducting films up to 2 μm on LaMnO 3 -buffered metal tapes by pulsed laser deposition. An interface engineering strategy, alternating growth of a 10 nm-thick nonsuperconducting FST seed layer and a 400 nmthick FST superconducting layer, was employed to guarantee the crystalline quality of the films with thicknesses of the order of micrometers, resulting in a highly biaxial texture with grain boundary misorientation angle less than the critical value θ c ∼ 9°. Moreover, the thickness effect, that the critical current density (J c ) shows a clear dependence on thickness as in cuprates, is reduced by the interface engineering. Also, the maximum J c was found for a 400 nm-thick film with 1.3 MA/cm 2 in self-field at 4.2 K and 0.71 MA/cm 2 (H∥ab) and 0.50 MA/cm 2 (H∥c) at 9 T. Anisotropic Ginzburg−Landau scaling indicates that the major pinning centers vary from correlated to uncorrelated as the film thickness increases, while the thickness effect is most likely related to the weakening of flux pinning by the fluctuation of charge-carrier mean free path (δl) and strengthening of flux pinning caused by the variation of superconducting transition temperature (δT c ) due to offstoichiometry with thickness.

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“…[6] Variations in the composition, including stoichiometry and mixed phases, have also been implemented to modify the electronic structure of materials or obtain synergic effects of different phases. [7][8][9][10][11][12] The microstructure and composition of thin films can be engineered by adjusting the film deposition conditions or performing postdeposition treatments that consider the intrinsic properties of the material.…”

Section: Introductionmentioning

confidence: 99%

Effects of Heat Treatment on the Microstructure and Optical Properties of Sputtered GeO₂ Thin Films

Nam

Bae

et al. 2023

Adv Eng Mater

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Microstructure and composition significantly influence the physical properties of thin films. Therefore, these can be adapted to enhance the functionality of thin films for practical applications. Herein, the anomalous microstructural evolution of sputtered GeO2 thin films based on postdepositional heat treatments is reported. Temperature‐dependent microstructural variations are investigated systematically via a combinatorial postdepositional heat treatment employing a natural thermal gradient in a tube furnace. Heat treatment under an oxidizing atmosphere results in a transition from the amorphous phase to the quartz phase, and subsequent heat treatments under a reducing atmosphere cause H2O‐incorporated chemical reactions. Hence, these conditions create unique microstructural features and yield optical transmittance variations in the GeO2 thin films. The phase transition induces the formation of spherulitic hexagonal GeO2 crystallites, and further increase in the temperature promotes the agglomeration of crystallites in the amorphous matrix. The incorporation of H2O results in the growth of the microstructure, and the chemical reduction to Ge metal begins to generate small granules from the boundary of the microstructures. The experimental results and proposed mechanisms presented herein for the microstructural and compositional changes serve as references for designing the physical properties of thin films.

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

Cited by 16 publications

References 43 publications

Reassembled phase diagram for Fe_ySe_xTe_1−x superconducting films grown by pulsed laser deposition

Reassembled phase diagram for Fe_ySe_xTe_1−x superconducting films grown by pulsed laser deposition

Critical Role Played by Interface Engineering in Weakening Thickness Dependence of Superconducting and Structural Properties of FeSe_0.5Te_0.5-Coated Conductors

Effects of Heat Treatment on the Microstructure and Optical Properties of Sputtered GeO₂ Thin Films

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

Cited by 16 publications

References 43 publications

Reassembled phase diagram for Fe y Se x Te1−x superconducting films grown by pulsed laser deposition

Reassembled phase diagram for Fe y Se x Te1−x superconducting films grown by pulsed laser deposition

Critical Role Played by Interface Engineering in Weakening Thickness Dependence of Superconducting and Structural Properties of FeSe0.5Te0.5-Coated Conductors

Effects of Heat Treatment on the Microstructure and Optical Properties of Sputtered GeO2 Thin Films

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Reassembled phase diagram for Fe_ySe_xTe_1−x superconducting films grown by pulsed laser deposition

Reassembled phase diagram for Fe_ySe_xTe_1−x superconducting films grown by pulsed laser deposition

Critical Role Played by Interface Engineering in Weakening Thickness Dependence of Superconducting and Structural Properties of FeSe_0.5Te_0.5-Coated Conductors

Effects of Heat Treatment on the Microstructure and Optical Properties of Sputtered GeO₂ Thin Films