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Robustness of superconductivity to structural disorder in Sr0.3(NH2)y(NH3)1−yFe2Se2

DOI: 10.1103/PhysRevB.92.134517 DOI Help

Authors: F. R Foronda (University of Oxford) , S. Ghannadzadeh (University of Oxford; Radboud University) , S. J. Sedlmaier (University of Oxford) , J. D. Wright (University of Oxford) , K. Burns (University of Oxford) , S. J. Cassidy (University of Oxford) , P. A. Goddard (University of Warwick) , T. Lancaster (Durham University) , S. J. Clarke (University of Oxford) , S. J. Blundell (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review B , VOL 92 (13)

State: Published (Approved)
Published: October 2015
Diamond Proposal Number(s): 11569

Abstract: 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.

Subject Areas: Chemistry, Physics, Materials

Instruments: I11-High Resolution Powder Diffraction

Other Facilities: MuSR at ISIS; GPS at Swiss Muon Source, Paul Scherrer Institut; ID31 at ESRF

Added On: 03/11/2015 16:18

Discipline Tags:

Superconductors Quantum Materials Physics Physical Chemistry Hard condensed matter - structures Chemistry Materials Science

Technical Tags:

Diffraction X-ray Powder Diffraction