Thermodynamic phase diagram of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mtext>Fe</mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mrow><mml:mtext>Se</mml:mtext></mml:mrow><mml:mrow><mml:mn>0.5</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mtext>Te</mml:mtext></mml:mrow><mml:mrow><mml:mn>0.5</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math>single crystals in fields up to 28 tesla

Klein, Thierry; Braithwaite, D.; Demuer, A.; Knafo, William; Lapertot, G.; Marcenat, C.; Rodière, Pierre; Sheikin, I.; Strobel, Pierre; Sulpice, A.; Toulemonde, Pierre

doi:10.1103/physrevb.82.184506

Cited by 89 publications

(127 citation statements)

References 60 publications

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“…Moreover, It has been reported that the zero temperature upper critical field of disordered superconductor shows deviation from the conventional one band WHH model and the observed values of H C2 (0) are smaller than the estimated values from conventional WHH model. [31][32][33][34][35][36][37][38] Similar deviation is also expected in our measurements. The broadening of the superconducting transition width in applied magnetic field is strongly related to the thermally activated flux flow mechanism.…”

Section: Resultssupporting

confidence: 76%

Superconducting, magnetic and magnetotransport properties of FeTe1-xSex single crystals

2018

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The single crystalline samples with compositions FeTe1-xSex (0.25 ≤ x ≤ 0.50) have been prepared via self-flux method and the superconducting, magnetic and magnetotransport properties of the grown crystals were investigated. The superconducting onset temperatures have been determined from the measurements of zero field cooled magnetization and resistance with temperatures. In the present case, highest superconducting transition temperature TC (onset) ∼ 15 K has been obtained for x=0.5. The HC2 (T=0 K) values have been estimated by fitting the experimental HC2 - T plots with WHH model. The highest HC2(0) has been obtained for x=0.5. The activation energy of the thermally activated flux flow has been found from the broadening of superconducting transition in an applied magnetic field using the Arrhenius law. Our results show that the activation energy (U0) decreases with the increasing magnetic field. Furthermore, the magnetization measurements for x=0.4 and 0.5 samples have been performed at T=5 K in the magnetic field range ±7 T to estimate critical current density at different applied magnetic fields using Bean formula. We see that the sample x=0.5 has higher values of JC as compared to that of x=0.4 at all magnetic fields. This is in conformity with the behavior of U0–H plots.

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Section: Resultssupporting

confidence: 76%

Superconducting, magnetic and magnetotransport properties of FeTe1-xSex single crystals

2018

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“…[23][24][25][26]29 Muon spin rotation (µSR) measurements in FeSe x are consistent with either anisotropic s-wave or a two-gap extended s-wave pairing. 23 Microwave cavity perturbation technique determined both real and imaginary parts of the com- Table I plex impedance and, in addition to λ(T ), could also estimate temperature -dependent scattering time from which a crossover from dirty to a clean limit upon cooling has been proposed.…”

mentioning

confidence: 64%

Precision global measurements of London penetration depth in FeTe0.58Se0.42

et al. 2011

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We report tunnel diode resonator measurements of in-plane London penetration depth, λ(T ), in optimally-doped single crystals of Fe(Te0.58Se0.42) with Tc ∼ 14.8 K. To avoid any size-dependent calibration effect, six samples of different sizes and deliberately introduced surface roughness were measured and compared. The power-law behavior, ∆λ(T ) = AT n , was found for all samples with the average exponent navg = 2.3 ± 0.1 and the pre-factor Aavg = 1.0 ± 0.2 nm/K 2.3 . The average superfluid density is well described by the self-consistent two-gap γ model resulting in ∆ I (0)/kBTc = 1.93 and ∆ II (0)/kBTc = 0.9. These results suggest the nodeless two-gap pairing symmetry with strong pair breaking effects. In addition, it is found from comparison among six different samples that while the exponent n remains virtually unchanged, the pre-factor A shows some variation, but stays within reasonable margin ruling out some recent suggestions that surface conditions can significantly affect the results. This indicates that the calibration procedure used to obtain λ(T ) from the measured TDR frequency shift is robust and that the uncertainty in sample dimensions and the nature of surface roughness play only a minor role.

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“…2(e)] we find a decay length of ξ = 1.30 nm, in good agreement with the coherence length obtained from H c2 of 1.5 nm. 23 …”

Section: Spatial Inhomogeneity Of the Chemical Composition And Smentioning

confidence: 99%

Spatial inhomogeneity of the superconducting gap and order parameter in FeSe0.4Te0.6

et al. 2013

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We have performed a low-temperature scanning tunneling microscopy and spectroscopy study of the iron chalcogenide superconductor FeSe 0.4 Te 0.6 with T C ≈ 14 K. Spatially resolved measurements of the superconducting gap reveal substantial inhomogeneity on a nanometer length scale. Analysis of the structure of the gap seen in tunneling spectra by comparison with calculated spectra for different superconducting order parameters (s-wave, d-wave, and anisotropic s-wave) yields the best agreement for an order parameter with anisotropic s-wave symmetry with an anisotropy of ∼40%. The temperature dependence of the superconducting gap observed in places with large and small gap size indicates that it is indeed the superconducting transition temperature which is inhomogeneous. The temperature dependence of the gap size has been found to differ from the one predicted by BCS theory. An analysis of the local gap size in relation to the local chemical composition shows almost no correlation with the local concentration of Se/Te atoms at the surface.

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Thermodynamic phase diagram ofFe(Se0.5Te0.5)single crystals in fields up to 28 tesla

Cited by 89 publications

References 60 publications

Superconducting, magnetic and magnetotransport properties of FeTe1-xSex single crystals

Superconducting, magnetic and magnetotransport properties of FeTe1-xSex single crystals

Precision global measurements of London penetration depth in FeTe0.58Se0.42

Spatial inhomogeneity of the superconducting gap and order parameter in FeSe0.4Te0.6

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