High thermal stability associated with supermodulus effect found in Ag Pd multilayer films

The Young's modulus E-f and interdiffusion in Ag/Pd metallic multilayers (M MLs) were measured. The supermodulus effect (SME) beyond 100% is found for the modulation wavelength lambda between 1.5 and 5 nm, where E-f shows loca l maximums at around lambda = 1.9, 2.8 and 3.7 nm or oscillations with incr easing lambda. In the high-SME MMLs, the activation enthalpy for interdiffu sion is found to be anomalously high, suggesting that the interatomic poten tial is increased as a whole due to a certain modulation in the electron sy stem. (C) 1999 Elsevier Science B.V. All rights reserved.