  In nonsuperconducting, metallic paramagnetic SrCo2As2, inelastic neutron
scattering measurements have revealed strong stripe-type $\chi$(q) = ($\pi$,0)
antiferromagnetic (AFM) spin correlations. Here, using nuclear magnetic
resonance (NMR) measurements on 59Co and 75As nuclei, we demonstrate that
stronger ferromagnetic (FM) spin correlations coexist in SrCo2As2. Our NMR data
are consistent with density functional theory (DFT) calculations which show
enhancements at both q = ($\pi$,0) and the in-plane FM q = 0 wavevectors in
static magnetic susceptibility $\chi$(q). We suggest that the strong FM
fluctuations prevent superconductivity in SrCo2As2, despite the presence of
stripe-type AFM fluctuations. Furthermore, since DFT calculations have
consistently revealed similar enhancements of the $\chi$(q) at both q =
($\pi$,0) and q = 0 in the iron-based superconductors and parent compounds, our
observation of FM correlations in SrCo2As2 calls for detailed studies of FM
correlations in the iron-based superconductors.
