X-Ray diffraction measurement of Poisson's ratio in Mo sublayers of Ni/Mo multilayers

Elasticity in low dimensional systems is still misunderstood although numerous experimental and theoretical studies on this subject have been done since the 1990s. Recently, we developed a new X-ray diffraction method based on in situ tensile deformation of the film/substrate set to investigate the elastic properties of both the film and the substrate and in particular to extract in a simple way the Poisson's ratio of the film. This method has been applied to study a polycrystalline stratified system composed of 13 bilayers (15 nm nickel and 8 nm molybdenum thick layers for each bilayer), deposited on a Duralumin substrate. The Mo Poisson's ratio has been determined; its value is close to the bulk one for the studied thickness. In addition, the applied strain transmission through the film/substrate interface has been analysed. (C) 2002 Elsevier Science B.V. All rights reserved.