Hamburg 2001 – scientific programme

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M: Metallphysik

M 11: Diffusion und Punktdefekte III

M 11.2: Fachvortrag

Monday, March 26, 2001, 15:30–15:45, S12

Correlation factors of diffusion and isotope effect in disordered structures — •Nikolaii P. Lazarev¹, Christian Abromeit², Alexander S. Bakai¹, and Volkmar Naundorf² — ¹NSC Kharkov Institute of Physics and Technology, Kharkiv, Ukraine — ²Hahn-Meitner-Institut Berlin GmbH

An extensive Monte Carlo simulation of diffusion in binary alloys is performed for disordered lattices with both random barriers and random traps. The concentration dependent correlation factors are derived for the vacancy mechanism. Anomalous dependencies of the correlation factors on composition and energetic disorder are observed. Contrary to diffusion in regular crystalline lattices where isotope effect nearly coincides with appropriate correlation factor its magnitude essentially depends on the energetic disorder in the random lattice. The isotope effect is found to be considerable reduced in the disorder structures. This is attributed to percolation processes which result from a reduction of the effective dimensionality of diffusion paths with increasing of disorder.