Low energy magnetic excitations from the   Fe$_{1+y-z}$(Ni/Cu)$_{z}$Te$_{1-x}$Se$_{x}$ system
  We report neutron scattering measurements on low energy ($\hbar\omega \sim 5$~meV) magnetic excitations from a series of Fe$_{1+y-z}$(Ni/Cu)$_{z}$Te$_{1-x}$Se$_{x}$ 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. 
Zhijun Xu, Jinsheng Wen, J. Schneeloch, A. D. Christianson, R. J.   Birgeneau, Genda Gu, J. M. Tranquada, and Guangyong Xu
cond-mat.supr-con