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 (MMLs) 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 local maximums at around lambda = 1.9, 2.8 and 3.7 nm or oscillations with increasing lambda. In the high-SME MMLs, the activation enthalpy for interdiffusion is found to be anomalously high, suggesting that the interatomic potential is increased as a whole due to a certain modulation in the electron system. (C) 1999 Elsevier Science B.V. All rights reserved.