  The tiny Ag diffusion to MgCNi3 has been prepared by solid states reaction.
Its structure was characterized by X-ray diffractometer (XRD). The results show
that a small mount of Ag substitute for Ni sites, and much of Ag are in vacancy
sites of the MgCNi3. We have further studied the surface properties of
Ag-MgCNi3 using Raman scattering spectra, and X-ray photoemission spectra
(XPS). Raman spectroscopy shows that the Ag-MgCNi3 has a special Raman peak
around 842.1 cm-1 compared to that of C. The superconductor transition
temperature (about 6.6 K) of Ag-MgCNi3 was lower than that of pure MgCNi3. It
was interpreted properly by the conventional BCS phonon mechanism.
