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Author (up) Seyfarth, G.; Jaccard, D.; Pedrazzini, P.; Krzton-Maziopa, A.; Pomjakushina, E.; Conder, K.; Shermadini, Z.
Title Pressure cycle of superconducting Cs0.8Fe2Se2 : A transport study Type Journal Article
Year 2011 Publication Solid State Communications Abbreviated Journal Solid State Commun.
Volume 151 Issue 10 Pages 747-750
Keywords Fe; Se; chalcogenides; Superconductivity; High pressure; electrical resistivity
Abstract We report measurements of the temperature and pressure dependence of the electrical resistivity (ρ) of single-crystalline iron-based chalcogenide Cs0.8Fe2Se2. In this material, superconductivity with a transition temperature Tc~30K source develops from a normal state with extremely large resistivity. At ambient pressure, a large “hump” in the resistivity is observed around 200 K. Under pressure, the resistivity decreases by two orders of magnitude, concomitant with a sudden Tc suppression around pc~30K. Even at 9 GPa a metallic resistivity state is not recovered, and the ρ(T) “hump” is still detected. A comparison of the data measured upon increasing and decreasing the external pressure leads us to suggest that the superconductivity is not related to this hump.
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Call Number BT @ pedrazp @ Serial 604
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Author (up) Yadav, C.S.; Seyfarth, G.; Pedrazzini, P.; Wilhelm, H.; Cerný, R.; Jaccard, D.
Title Effect of pressure cycling on Iron: Signatures of an electronic instability and unconventional superconductivity Type Journal Article
Year 2013 Publication Physical Review B Abbreviated Journal Phys. Rev. B
Volume 88 Issue 5 Pages 054110-7
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Abstract High pressure electrical resistivity and x-ray diffraction experiments have been performed on Fe single crystals. The crystallographic investigation provides direct evidence that in the martensitic $bcc \rightarrow hcp$ transition at 14 GPa the $\lbrace 110\rbrace{bcc}$ become the $\lbrace 002\rbrace{hcp}$ directions. During a pressure cycle, resistivity shows a broad hysteresis of 6.5 GPa, whereas superconductivity, observed between 13 and 31 GPa, remains unaffected. Upon increasing pressure an electronic instability, probably a quantum critical point, is observed at around 19 GPa and, close to this pressure, the superconducting $T{c}$ and the isothermal resistivity ($0<T<300\,$K) attain maximum values. In the superconducting pressure domain, the exponent $n = 5/3$ of the temperature power law of resistivity and its prefactor, which mimics $T{c}$, indicate that ferromagnetic fluctuations may provide the glue for the Cooper pairs, yielding unconventional superconductivity.
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Publisher American Physical Society Place of Publication Editor
Language English Summary Language Original Title
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Notes Approved no
Call Number BT @ pedrazp @ Serial 658
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