NMR Characterization of Sulphur Substitution Effects in the   K(x)Fe(2-y)Se(2-z)S(z) high Tc Superconductor
  We present an NMR study of the effect of S substitution in the high Tc superconductor K(x)Fe(2-y)Se(2-z)S(z) in a temperature range up to 250 K. We present NMR Knight shift and nuclear spin-lattice relaxation rate 1/T1 data, and compare our results to that of the non-substituted system K(x)Fe(2-y)Se(2). 
D. A. Torchetti, T. Imai, H. C. Lei, and C. Petrovic
cond-mat.supr-con