Low-energy magnetic excitations from the Fe1+y−z(Ni/Cu)zTe1−xSex system

We report neutron scattering measurements on low-energy (â.,ωâ5 meV) magnetic excitations from a series of Fe1+yâz(Ni/Cu)zTe1âxSex samples which belong to the “11†Fe-chalcogenide family. Our results suggest a strong correlation between the magnetic excitations near (0.5,0.5,0) and the superconducting properties of the system. The low-energy magnetic excitations are found to gradually move away from (0.5,0.5,0) to incommensurate positions when superconductivity is suppressed, either by heating or chemical doping, confirming previous observations. © 2014 American Physical Society.