Abinitio molecular dynamics model for density, elastic properties and short range order of Co-Fe-Ta-B metallic glass thin films

Abstract

Density, elastic modulus and the pair distribution function of Co-Fe-Ta-B metallic glasses were obtained by abinitio molecular dynamics simulations and measured for sputtered thin films using x-ray reflectivity, nanoindentation and x-ray diffraction using high energy photons. The computationally obtained density of 8.19gcm3 for Co43Fe20Ta 5.5B31.5 and 8.42gcm3 for Co 45.5Fe24Ta6B24.5, as well as the Youngs moduli of 273 and 251GPa, respectively, are consistent with our experiments and literature data. These data, together with the good agreement between the theoretical and the experimental pair distribution functions, indicate that the model established here is useful to describe the density, elasticity and short range order of Co-Fe-Ta-B metallic glass thin films. Irrespective of the investigated variation in chemical composition, (Co, Fe)B cluster formation and CoFe interactions are identified by density-of-states analysis. Strong bonds within the structural units and between the metallic species may give rise to the comparatively large stiffness. © 2011 IOP Publishing Ltd.