Microstructural magnetic phases in superconducting FeTe0.65Se0.35

Abstract

In this paper, we address a number of outstanding issues concerning the nature and the role of magnetic inhomogenities in the iron chalcogenide system FeTe1-xSex and their correlation with superconductivity in this system. We report morphology of superconducting single crystals of FeTe0.65Se0.35 studied with transmission electron microscopy, high angle annular dark field scanning transmission electron microscopy and their magnetic and superconducting properties characterized with magnetization, specific heat and magnetic resonance spectroscopy. Our data demonstrate a presence of nanometre scale hexagonal regions coexisting with tetragonal host lattice, a chemical disorder demonstrating non homogeneous distribution of host atoms in the crystal lattice, as well as hundreds-of-nanometres-long iron-deficient bands. From magnetic data and ferromagnetic resonance temperature dependence, we attribute magnetic phases in Fe-Te-Se to Fe3O4 inclusions and to hexagonal symmetry nanometre scale regions with structure of Fe7Se8 type. Our results suggest that nonhomogeneous distribution of host atoms might be an intrinsic feature of superconducting Fe-Te-Se chalcogenides and we find a surprising correlation indicating that faster grown crystal of inferior crystallographic properties is a better superconductor.

16 pages, 8 figures, 2 tables

References in corpus (14)

• High-temperature superconductivity in iron-based materials
• Superconductivity at 36 K in beta-Fe1.01Se with the compression of the interlayer separation under pressure
• Incommensurate magnetic order in the alpha-Fe(Te,Se) superconductor systems
• First-order magnetic and structural phase transitions in Fe${}_{1+y}$Se${}_x$Te${}_{1-x}$
• Bulk Superconductivity at 14 K in Single Crystals of Fe1+yTexSe1-x
• From (pi, 0) magnetic order to superconductivity with (pi, pi) magnetic resonance in Fe1.02(Te1-xSex)
• On the multi-orbital band structure and itinerant magnetism of iron-based superconductors
• Fabrication of the iron-based superconducting wire using Fe(Se, Te)
• Physical properties of FeSe${}_{0.5}$Te${}_{0.5}$ single crystals grown under different conditions
• Evidence of local structural inhomogeneity in FeSe(1-x)Te(x) from extended x-ray absorption fine structure
• Stripes, spin resonance and $d_{x^2-y^2}-$pairing symmetry in FeSe-based layered superconductors
• Optical conductivity of superconducting Rb2Fe4Se5
• On the consistency of the Aoki-phase
• Mössbauer studies of powdered single crystals of FeTe0.5Se0.5

Cited by in corpus (7)

• Superconductivity and magnetism in RbxFe2-ySe2: Impact of thermal treatment on mesoscopic phase separation
• The substitution effects on electronic structure of iron selenide superconductors
• Microstructural and transport properties of superconducting FeTe0.65Se0.35 crystals
• Transition-Metal Substitutions in Iron Chalcogenides
• Intrinsic pinning by naturally occurring correlated defects in FeSe${}_{\text{1-x}}$Te${}_{\text{x}}$ superconductors
• Anisotropy of the magnetic properties of the FeTe0.65Se0.35 superconductor
• Dynamics of trapped magnetic flux in superconducting FeTe0.65Se0.35