Antiferromagnetic fluctuations in Fe(Se1-xTex)0.92 (x = 0.75, 1) observed by inelastic neutron scattering

Abstract

Motivated by the discovery of superconductivity in F-doped LaFeAsO, we investigated the magnetic fluctuations in a related compound Fe(Se1-xTex)0.92 (x = 0.75, 1) using neutron scattering techniques. Non-superconducting FeTe0.92 shows antiferromagnetic (AF) ordering with the ordering vector |Q| = 0.97 A-1 (Q = (0.5,0,0.5)) at TN ~ 70 K and a structural transition between tetragonal and monoclinic phases. In the AF monoclinic phase, the low-energy spectral weight is suppressed, indicating a possible gap formation. On the other hand, in the paramagnetic tetragonal phase, we observed a pronounced magnetic fluctuation around at |Q| ~ 0.92 A-1, which is slightly smaller than the commensurate value. In Fe(Se0.25Te0.75)0.92, which does not show magnetic ordering and shows superconductivity at Tc ~ 8 K, we observed that a magnetic fluctuation is located at |Q| ~ 0.9 A-1 at low energies and shifts to a higher value of |Q| ~ 1.2 A-1 at higher energies. The latter value is close to a reciprocal lattice vector Q = (0.5,0.5,0.5) or (0.5,0.5,0), where the AF fluctuations are observed in other FeAs-based materials. The existence of this common characteristic in different Fe-based superconductors suggests that the AF fluctuations may play a important role in superconductivity.

4 pages, 4 figures

References in corpus (13)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• Spin density wave anomaly at 140 K in the ternary iron arsenide BaFe2As2
• Density functional study of FeS, FeSe and FeTe: Electronic structure, magnetism, phonons and superconductivity
• Superconductivity close to magnetic instability in Fe(Se1-xTex)0.82
• 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${}_{1-x}$
• Crystal structure of the new FeSe1-x superconductor
• Low energy spin waves and magnetic interactions in SrFe${}_2$As${}_2$
• Anisotropic itinerant magnetism and spin fluctuations in BaFe2As2: A neutron scattering study
• High energy spin excitations in BaFe2As2
• Anisotropic three-dimensional magnetism in CaFe2As2
• Neutron scattering study of the oxypnictide superconductor La(O,F)FeAs

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