Nanoscale diffusion in Pt/56Fe/57Fe thin-film system

THIN SOLID FILMS

卷:589

Article

Tynkova, A.^1,2  Katona, G. L.¹  Erdelyi, G.¹  Daroczi, L.¹  Oleshkevych, A. I.²  Vladymyrskyi, I. A.²  Sidorenko, S. I.²  Voloshko, S. M.²  Beke, D. L.¹ 

[1] Univ Debrecen, Dept Solid State Phys, H-4010 Debrecen, Hungary

[2] Natl Tech Univ Ukraine, Kyiv Polytech Inst, UA-03056 Kiev, Ukraine

关键词: Interdiffusion;    Grain-boundary diffusion;    Self-diffusion;    Nanostructure;   

DOI  :  10.1016/j.tsf.2015.04.069

来源: Elsevier

【 摘 要 】

Low-temperature diffusion of Fe in Pt/Fe-56/Fe-57 thin films (grown on MgO (100) substrate) was investigated between 703 K and 813 K using secondary neutral mass spectrometry. The activation energy of the effective interdiffusion coefficients, evaluated by the centre-gradient method, is 1.53 +/- 0.25 eV reflecting a strong contribution from grain boundaries. This is also supported by the observed deep penetrations of Pt into the Fe-56 layer, from which the grain boundary diffusion coefficients for Pt in Fe were also estimated and 1.45 +/- 0.25 eV activation energy was obtained. A simple model, including the effect of grain boundaries to the overall intermixing at the original sharp interfaces in nanocrystalline films, is developed. This predicts that at short annealing times the grain boundary diffusion dominates, and bulk diffusion coefficients can be determined only in long time limit. At intermediate annealing times, when the grain boundaries are saturated but the bulk diffusion is still negligible, there are no changes in the composition profiles. This yields good qualitative agreement with the experimental data and offers explanation for the time and temperature dependence of the interdiffusion coefficients obtained in similar systems. (C) 2015 Elsevier B.V. All rights reserved.

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