Effect of size on energy and elastic constants of Ni nanoparticles studied using the embedded-atom method

Using the embedded-atom method potential, the energy and elastic constants of Ni nanoparticles are investigated as a function of size. It is found that a simple formula derived from the total energy can be used to explain the change characteristics of the size-dependent energy and C-11 and C-44 of Ni nanoparticles. The change characteristics of the size-dependent C-12 are slightly different from the situation of C-11 and C-44 and they perhaps depend on its strain character when the nanoparticle is larger than similar to 2.0 nm in size. It is also found that a transition occurs from a fast change of these size-dependent properties to a slow one. Such a transition occurs at similar to 1.5 nm in size for the nanoparticles, i.e. the energy and elastic constants of Ni nanoparticles show approximately no change as long as their size is larger than 2 nm. It is also demonstrated that when the size of the nanoparticle is large enough (>20 nm) the calculated elastic constants and the cohesive energy are in agreement with those of their respective bulk counterpart.