  We report a novel superconducting (SC) and antiferromagnetic (AF) hybrid
state in SrFe2As2 revealed by 75As nuclear magnetic resonance (NMR) experiments
on a single crystal under highly hydrostatic pressure up to 7 GPa. The NMR
spectra at 5.4 GPa indicate simultaneous development of the SC and AF orders
below 30 K. The nuclear spin-lattice relaxation rate in the SC domains shows a
substantial residual density of states, suggesting proximity effects due to
spontaneous formation of a nano-scale SC/AF hybrid structure. This entangled
behavior is a remarkable example of a self-organized heterogeneous structure in
a clean system.
