Magnetic excitations of Fe(1+y)Se(x)Te(1-x) in magnetic and superconductive phases.

Journal article

We have used inelastic neutron scattering and muon-spin rotation to compare the low energy magnetic excitations in single crystals of superconducting Fe(1.01)Se(0.50)Te(0.50) and non-superconducting Fe(1.10)Se(0.25)Te(0.75). We confirm the existence of a spin resonance in the superconducting phase of Fe(1.01)Se(0.50)Te(0.50), 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) ± (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 Fe(1.10)Se(0.25)Te(0.75) close to the commensurate antiferromagnetic ordering wavevector (1/2 - δ, 0, 1/2), where δ≈0.03. The magnetic correlations in both samples are found to be quasi-two-dimensional in character and persist well above the magnetic (Fe(1.10)Se(0.25)Te(0.75)) and superconducting (Fe(1.01)Se(0.50)Te(0.50)) transition temperatures.

Authors: Babkevich, P; Bendele, M; Boothroyd, A; Conder, K; Gvasaliya, SN

• Publication status: Published
• Journal: Journal of physics. Condensed matter : an Institute of Physics journal
• Volume: 22
• Issue: 14
• Pages: 142202
• Publication date: 2010-04-01
• DOI: 10.1088/0953-8984/22/14/142202
• EISSN: 1361-648X
• ISSN: 0953-8984
• Language: English
• Keywords: cond-mat.supr-con