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arXiv · 1003.0539

Magnetic excitations of Fe_{1+y}Se_xTe_{1-x} in magnetic and superconductive phases

P. Babkevich·M. Bendele·A. T. Boothroyd·K. Conder·S. N. Gvasaliya·R. Khasanov·E. Pomjakushina·B. Roessli
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Abstract

We have used inelastic neutron scattering and muon-spin rotation to compare the low energy magnetic excitations in single crystals of superconducting Fe1.01Se0.50Te0.50 and non-superconducting Fe1.10Se0.25Te0.75. We confirm the existence of a spin resonance in the superconducting phase of Fe1.01Se0.50Te0.50, at an energy of 7 meV and a wavevector of (1/2,1/2,0). The non-superconducting sample exhibits two incommensurate magnetic excitations at (1/2,1/2,0)\pm(0.18,-0.18,0) which rise steeply in energy, but no resonance is observed at low energies. A strongly dispersive low-energy magnetic excitation is also observed in Fe1.10Se0.25Te0.75 close to the commensurate antiferromagnetic ordering wavevector (1/2-δ,0,1/2) where δ\approx 0.03. The magnetic correlations in both samples are found to be quasi-two dimensional in character and persist well above the magnetic (Fe1.10Se0.25Te0.75) and superconducting (Fe1.01Se0.50Te0.50) transition temperatures.

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P. Babkevich, M. Bendele, A. T. Boothroyd, K. Conder, S. N. Gvasaliya, R. Khasanov, E. Pomjakushina, B. Roessli. 2010-03-19. Magnetic excitations of Fe_{1+y}Se_xTe_{1-x} in magnetic and superconductive phases. https://doi.org/10.1088/0953-8984%2F22%2F14%2F142202

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