Elastic and inelastic mean free paths of 200keV electrons in metallic glasses.

The elastic and inelastic mean free paths of three metallic glass alloys, Ni60 Nb40 , Pd82 Si18 and Ni80 P20 , have been measured from focused ion beam prepared thin samples with measured thickness gradients. The elastic/inelastic mean free paths of the three alloys are 35±0.5/97±3, 26±0.5/148±3 and 40±0.5/129±2.5nm, respectively. Elastic mean free paths predicted from atomic scattering cross sections consistently underestimate the experimental data. A model based on the Wentzel atomic model was developed and the fit to available data is in much better agreement with experiments, with a maximum deviation of ~4nm. The parametrized model is thus capable of predicting the elastic mean free path for other amorphous materials. Existing models for the inelastic mean free path are not in good agreement with the experimental data.