Determination of grain-boundary diffusion of Ag in nanocrystalline Cu by the Hwang–Balluffi method

From the Ag and Cu Auger signals measured on the surface of nanocrystalline Cu/Ag thin bilayers, the temperature dependence of the parameter ω′ for Ag grain-boundary diffusion in Cu (ω′=δkbDb/δsks, where δ and δs are the width of the grain boundary and the segregated layer and kb and ks are the grain-boundary and surface segregation factors, respectively) have been determined by the Hwang–Balluffi method in the C-kinetics regime over the temperature range of 393–428 K. These values have been compared with triple products, P=δkbDb, determined in the temperature range 584–804 K by Bernardini et al. [Phil. Mag. A 73, 237 (1996)] using radio tracer technique in the B-kinetics regime and the temperature dependence of the surface segregation factor has been extracted. The surface segregation energy (34±16 kJ/mol) agrees well with other data published in the literature.