  In Ba(Fe0.95Co0.05)2As2 all of the 75As NMR intensity at the paramagnetic
resonance position vanishes abruptly below Tonset(SDW)=56 K, indicating that
magnetic (spin density wave) order is present in all of the sample volume,
despite bulk superconductivity below Tc=15 K. The two phases thus coexist
homogeneously at the microscopic scale. In Ba0.6K0.4Fe2As2, on the other hand,
the signal loss below Tonset(SDW)~75 K is not complete, revealing that magnetic
order is bound to finite-size areas of the sample, while the remaining NMR
signal shows a clear superconducting response below Tc=37 K. Thus, the two
phases are not homogeneously mixed, at least for this potassium concentration.
For both samples, spatial electronic and/or magnetic inhomogeneity is shown to
characterize the NMR properties in the normal state.
