12-15 July 2011
Saint George Hotel
Africa/Johannesburg timezone

The Surface Orientation Dependence of the Pre-Exponential Factors Extracted from the Segregation Profiles of a Cu(111/110) Bi-crystal

13 Jul 2011, 17:00


Poster Presentation Track A - Condensed Matter Physics and Material Science Poster1


Mr Charl Jafta (Energy and Processes Unit, CSIR)


Previous experimental investigations have only shown, without explanation, that the pre-exponential factor (D0), in the diffusion coefficient of Sb segregating in Cu, is dependent on the surface orientation of a crystal. In this study, the surface concentration of Sb in a Sb doped Cu(111/110) bi-crystal was measured using a method combining AES and linear temperature heating. Segregation parameters, including the D0’s are extracted from the experimental data of surface concentration versus temperature using the modified Darken model. The difference in the two pre-exponential factors D0 (Sb in Cu(111)) and D0 (Sb in Cu(110)) is explained thermodynamically in terms of entropy change ΔS that is calculated, for the first time, for a Cu(111/110) bi-crystal.

Consider for a student <br> &nbsp; award (Yes / No)? Yes
Level (Hons, MSc, <br> &nbsp; PhD, other)? MSc
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)? Yes

Primary author

Mr Charl Jafta (Energy and Processes Unit, CSIR)


Prof. Jacobus Terblans (Physics Department, University of the Free State) Dr Joseph Asante (Physics Department, Tshwane University of Technology) Prof. Kenneth Ozoemena (Energy and Processes Unit, CSIR) Prof. Wiets Roos (Physics Department, University of the Free State)

Presentation Materials