  Spin-flip mechanism in Ag nanowires with MgO surface protection layers has
been investigated by means of nonlocal spin valve measurements using
Permalloy/Ag lateral spin valves. The spin flip events mediated by surface
scattering are effectively suppressed by the MgO capping layer. The spin
relaxation process was found to be well described in the framework of
Elliott-Yafet mechanism and then the probabilities of spin-filp scattering for
phonon or impurity mediated momentum scattering is precisely determined in the
nanowires. The temperature dependent spin-lattice relaxation follows the
Bloch-Gr\"uneisen theory and falls on to a universal curve for the monovalent
metals as in the Monod and Beuneu scaling determined from the conduction
electron spin resonance data for bulk.
