Homogeneity Range of Ternary 11-Type Chalcogenides Fe1 + y
            Te1−x
            Se
                x

Koz, Cevriye; Rößler, Sahana; Wirth, S.; Schwarz, Ulrich

doi:10.1007/s10948-016-3632-x

Cited by 5 publications

(4 citation statements)

References 18 publications

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“…Similar results of the suppression of superconductivity due to the increase in magnetic correlation length have been observed for excess Fe in Fe y Se 0.25 Te 0.75 [15]. Also, strong suppression in the superconducting volume fraction has been observed due to Fe excess in Fe 1+y Te 1−x Se x [16]. The variation of Fe in Fe y Te 0.60 Se 0.40 also leads to the tuning of the anisotropic behaviour [17].…”

Section: Introductionsupporting

confidence: 74%

Study of TAFF and vortex phase of Fe_xTe_0.60Se_0.40 (0.970 ≤ x ≤ 1.030) single crystals

Kumar¹,

Varma²

2020

Phys. Scr.

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Single crystalline samples with starting compositions FexTe0.60Se0.40 (x = 0.970, 0.985, 1, 1.015 and 1.030) have been grown using the self-flux method to study the effect of Fe variation (x) on the structural and superconducting properties of the grown single crystalline samples. All the grown samples are found superconducting and among all, the FeTe0.60Se0.40 (x = 1) sample shows the highest superconducting transition temperature (TC). For the samples with x other than 1, a decrease in the superconducting properties, such as TC, activation energy (U0) and upper critical field (HC2(0)), has been observed. The thermal activation energy (TAE) of the flux flow has been calculated using the conventional method and modified thermally activated flux flow (TAFF) model. The values of U0(H) show transition from the single vortex pinning regime to the collective vortex pinning regime at 2T. Also, the presence of planer defects has been estimated via both models. Furthermore, the modified TAFF model suggests three dimentional (3D) behaviour for all the grown single crystals. The vortex phase diagrams have been established by analysing the magnetoresistance data. The analysis reveals the transitions from unpinned to pinned vortex liquid region and also from the pinned vortex liquid state to vortex glass state. In the vortex phase diagram, below the critical temperature (T*), the critical exponent (s) is in a good agreement with the ‘q’ values for the 3D behaviour of vortex states for all the grown samples.

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Section: Introductionsupporting

confidence: 74%

Study of TAFF and vortex phase of Fe_xTe_0.60Se_0.40 (0.970 ≤ x ≤ 1.030) single crystals

Kumar¹,

Varma²

2020

Phys. Scr.

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“…In order to learn more about the disorder in this system, especially concerning the apparently large positional fluctuations within the Fe sub‐lattice, we plan to combine the XFH results with XAFS measurements at the Fe K edge of the same sample. These XFH results may also represent a starting point for further discussions on more curious features of the FeSe 1− x Te x structure, like the role of excess Fe; pure phases of this system can only be prepared with some amount of excess Fe, which is about 2–10% of the nominal Fe concentration in this composition, and which has a large impact on the superconducting properties. This can be realized by a state‐selective approach in order to enhance the visibility of the excess Fe atoms with a possibly lower oxidization state.…”

Section: Discussionmentioning

confidence: 86%

Local Structure of FeSe_0.4Te_0.6 by Low‐Temperature X‐Ray Fluorescence Holography

Stellhorn

Ideguchi

Kawasaki

et al. 2018

Physica Status Solidi (b)

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We present low‐temperature X‐ray fluorescence holography experiments to investigate the atomic scale structure of the high‐temperature superconductor FeSe0.4Te0.6. The results present a direct investigation of the local structure around the Fe atoms. Very clear images of the structure are obtained by a sparse modeling approach to the experimental data using a L1‐regularized linear regression. The results are in good agreement with previous findings of XRD and XAFS experiments on the FeSe1−xTex system, but furthermore indicate large fluctuations in the Fe sub‐lattice. The findings also represent a starting point for further discussions on more curious features of the FeSe1−xTex structure.

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“…For our study, the FeTe 1Àx Se x crystals with the tellurium content more than 50% were selected as the crystals with 1Àx < 0.5 turn out inhomogeneous originally. [8] When 1Àx < 0.5, prepared crystals are initially homogeneous (single phase) and they have poor superconductivity. [1,6,9] We investigated crystals immediately after growth in melts of the alkali metal halides [10] and after long-time keeping (2-3 years) in a desiccator in dry atmosphere.…”

Section: Resultsmentioning

confidence: 99%

“…This is typical for the Fe 1þy Te 1Àx Se x samples with high iron content. [8,31] It is interesting to know the formation of phases with the highly increased content of Te. The Bragg reflections numbered as 3 and 4 (Figure 3b) correspond to FeTe and the Fe 1þy Te 0.9 Se 0.1 compound accordingly.…”

Section: Resultsmentioning

confidence: 99%

Temporal Spinodal Decomposition of the Fe_1+yTe_1−xSe_x Crystals and its Impact on Superconducting Properties

Gimazov

Kiiamov

Sadakov

et al. 2022

Physica Status Solidi (b)

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Precipitated phases, formed by spinodal decomposition during long‐term storage in a desiccator in dry atmosphere, are found with the X‐ray diffraction (XRD) study of Fe1+y Te1−x Se x crystals. Their compositions are deduced from the position of satellite Bragg reflections in the XRD pattern. In particular, in the Fe1.19Te0.58Se0.42 crystal, traces of phases with significantly higher tellurium content, namely Fe1+y Te0.9Se0.1 and FeTe, are found. The detection and analysis of side bands in the diffraction pattern of an aged crystal indicate spinodal decay. It leads to the formation of a modulated structure in the entire volume of the sample and to strain in the crystal structure. In turn, this results in a significant improvement in the superconducting characteristics. Specifically, the resistive transition narrows to 2 K at the onset temperature 14.5 K, and the superconducting volume fraction increases up to about 100%.

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Homogeneity Range of Ternary 11-Type Chalcogenides Fe1 + y Te1−x Se x

Cited by 5 publications

References 18 publications

Study of TAFF and vortex phase of Fe_xTe_0.60Se_0.40 (0.970 ≤ x ≤ 1.030) single crystals

Study of TAFF and vortex phase of Fe_xTe_0.60Se_0.40 (0.970 ≤ x ≤ 1.030) single crystals

Local Structure of FeSe_0.4Te_0.6 by Low‐Temperature X‐Ray Fluorescence Holography

Temporal Spinodal Decomposition of the Fe_1+yTe_1−xSe_x Crystals and its Impact on Superconducting Properties

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Homogeneity Range of Ternary 11-Type Chalcogenides Fe1 + y Te1−x Se x

Cited by 5 publications

References 18 publications

Study of TAFF and vortex phase of FexTe0.60Se0.40 (0.970 ≤ x ≤ 1.030) single crystals

Study of TAFF and vortex phase of FexTe0.60Se0.40 (0.970 ≤ x ≤ 1.030) single crystals

Local Structure of FeSe0.4Te0.6 by Low‐Temperature X‐Ray Fluorescence Holography

Temporal Spinodal Decomposition of the Fe1+yTe1−xSex Crystals and its Impact on Superconducting Properties

Contact Info

Product

Resources

About

Study of TAFF and vortex phase of Fe_xTe_0.60Se_0.40 (0.970 ≤ x ≤ 1.030) single crystals

Study of TAFF and vortex phase of Fe_xTe_0.60Se_0.40 (0.970 ≤ x ≤ 1.030) single crystals

Local Structure of FeSe_0.4Te_0.6 by Low‐Temperature X‐Ray Fluorescence Holography

Temporal Spinodal Decomposition of the Fe_1+yTe_1−xSe_x Crystals and its Impact on Superconducting Properties