Y0.5Ca0.5BaCo4O7 was recently introduced as a possible candidate for capturing some of the predicted classical spin kagome ground state features. Stimulated by this conjecture we have taken up a more complete study of the spin correlations in this compound with neutron scattering methods on a powder sample characterized with high-resolution neutron diffraction and the temperature dependence of magnetic susceptibility and specific heat. We have found that the frustrated near neighbor magnetic

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... relations involve not only the kagome planes but concern the full Co sub-lattice as evidenced by the analysis of the wavevector-dependence of the short range order. We conclude from our results that the magnetic moments are located on the Co sub-lattice as a whole and that correlations extend beyond the two-dimensional kagome planes. We identify intriguing dynamical properties, observing high-frequency fluctuations with a lorentzian line-width Γ <= 20 meV at ambient temperature. On cooling a low-frequency ( 1 meV) dynamical component develops alongside the high-frequency fluctuations, which eventually becomes static at temperatures below T 50 K. The high-frequency response with an overall line-width of 10 meV prevails at T <= 2 K coincident with a fully elastic short-range ordered contribution.