Robustness of superconductivity to structural disorder inSr0.3(NH2)y(NH3)1

Abstract

. (2015) 'Robustness of superconductivity to structural disorder in Sr0.3(NH2)y(NH3)1yFe2Se2.', Physical review B., 92 (13). p. 134517.Further information on publisher's website:http://dx.doi.org/10.1103/PhysRevB. 92.134517 Publisher's copyright statement:Reprinted with permission from the American Physical Society: Physical Review B 92, 134517 c 2015 by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modied, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The superconducting properties of a recently discovered high-T c superconductor, Sr/ammonia-intercalated FeSe, have been measured using pulsed magnetic fields down to 4.2 K and muon spin spectroscopy down to 1.5 K. This compound exhibits intrinsic disorder resulting from random stacking of the FeSe layers along the c axis that is not present in other intercalates of the same family. This arises because the coordination requirements of the intercalated Sr and ammonia moieties imply that the interlayer stacking (along c) involves a translation of either a/2 or b/2 that locally breaks tetragonal symmetry. The result of this stacking arrangement is that the Fe ions in this compound describe a body-centered-tetragonal lattice in contrast to the primitive arrangement of Fe ions described in all other Fe-based superconductors. In pulsed magnetic fields, the upper critical field H c2 was found to increase on cooling with an upward curvature that is commonly seen in type-II superconductors of a multiband nature. Fitting the data to a two-band model and extrapolation to absolute zero gave a maximum upper critical field μ 0 H c2 (0) of 33(2) T. A clear superconducting transition with a diamagnetic shift was also observed in transverse-field muon measurements at T c ≈ 36.3(2) K. These results demonstrate that robust superconductivity in these intercalated FeSe systems does not rely on perfect structural coherence along the c axis.

Tetrahedral Transition Metal Chalcogenides as Functional Inorganic Materials

“…Using a similar liquid ammonia route, alkaline earth metals can also be intercalated into FeSe, despite achieving a slightly lower T c than the alkali metals. For Sr and Ba intercalation, the T c is found to be 35 K , and 36 K, respectively. Nonetheless, the compounds are quite remarkable considering that they cannot be prepared by conventional solid-state methods.…”

Critical current density and vortex pinning in tetragonalFeS1−xSex(x=0,0.06)

“…[15][16][17][18] Since FeCh tetrahedra could be incorporated in different superconducting materials, it is of interest to study critical currents and vortex pinning mechanism in tetragonal FeS. [19][20][21] Moreover, vortex pinning and dynamics is strongly related to coherence length and superconducting pairing mechanism.…”

The intercalation chemistry of layered iron chalcogenide superconductors

“…Several groups soon demonstrated that a host of different electropositive metals besides lithium such as potassium, rare earths, and alkaline earths could be interca- lated into the FeSe sheets through the liquid ammonia method. [128,129,130,131,132] Ying et al found that the amount of K + cations inserted was more important for affecting T c than the amount of ammonia intercalated. [127] In their phase diagram, shown in Figure 12, the superconducting regime does not have a dome-like appearance but rather resembles three flat plateaus.…”