Comparison between Einstein and Debye models for an amorphous Ni46Ti54 alloy produced by mechanical alloying investigated using extended x-ray absorption fine structure and cumulant expansion

We investigated an amorphous Ni46Ti54 alloy produced by mechanical alloying using extended x-ray absorption fine structure (EXAFS) technique and cumulant expansion considering Einstein and Debye models for the temperature dependence of the cumulants. Results obtained from both models were compared and very similar values were obtained. From them, we found information about the structure of the alloy besides thermal and structural disorder, anharmonicity, thermal expansion, and asymmetry of the partial distribution functions g(ij)(r). The cumulants C-1*, C-2*, and C-3* also allowed us to reconstruct the g(ij) (r, T) functions from EXAFS. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3533960]