Hostname: page-component-76fb5796d-vfjqv Total loading time: 0 Render date: 2024-04-25T15:20:39.091Z Has data issue: false hasContentIssue false
  • English
  • Français

Chemical Ordering Along the Growth Direction in Epitaxial [0002] Co1−xRux Alloy Thin Films

Published online by Cambridge University Press:  10 February 2011

O. Ersen ,
L. Bouzidi ,
V. Pierron-Bohnes  and
M.C. Cadeville
O. Ersen
Affiliation:
IPCMS-GEMM, CNRS-ULP, 23 rue du Loess F-67037 Strasbourg, France
L. Bouzidi
Affiliation:
IPCMS-GEMM, CNRS-ULP, 23 rue du Loess F-67037 Strasbourg, France
V. Pierron-Bohnes
Affiliation:
IPCMS-GEMM, CNRS-ULP, 23 rue du Loess F-67037 Strasbourg, France
M.C. Cadeville
Affiliation:
IPCMS-GEMM, CNRS-ULP, 23 rue du Loess F-67037 Strasbourg, France
Get access

Abstract

The occurrence of metastable long range order (LRO) along the growth direction with a periodicity twice that of a disordered alloy is now a well established result in epitaxial hcp [0002] Co-Ru and Co-Pt alloy thin films. We first present a review of previous results obtained in Co-rich Co1−xRux alloy thin films (x = 0.25) prepared at various growth temperatures (TG) and the diffusive model developed to account for the observed behavior. This model which takes into account the competition between surface and bulk interactions and surface and bulk diffusion during the growth time reproduces the TG dependence of the LRO parameter (η) and of the lattice constants. Then we present new results on the occurrence of this LRO in Co1−xRux films for higher Ru concentrations (0.22 ≤ x ≤ 0.78) prepared at the optimal temperature for the occurrence of this LRO (570-595 K). Chemical ordering is observed over the whole explored concentration range and it is found to be in agreement with results obtained in a previous series prepared at 610 K with lower Ru content. The LRO parameter deduced from the difference in composition between two successive planes normalized with respect to the concentration of the minonty element displays a nearly symmetric dependence with concentration characterized by a maximum around x = 0.2 and a minimum around the equiatomic composition. These results are qualitatively discussed in terms of a balance between the different energetic contributions to the surface segregation that arise from the release of the elastic energy and the difference in the wetting energy of each element. The important role played by the quality of the substrate in determining the value of η is outlined.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 528: Symposia AA – Mechanisms & Principals of Epitaxial Growth in Metallic Systems , 1998 , 11
Copyright
Copyright © Materials Research Society 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

[1] Hansen, M., Constitution of Binary Alloys, McGraw-Hill, New York, 1958, p. 496.Google Scholar
[2] Pierron-Bohnes, V., Ringelstein, N., Michel, A., Boukari, S., Bouzidi, L., Persat, N., Beaurepaire, E., Hehn, M., Muller, D. and Cadeville, M. C., J. Magn. Magn. Mater., 165, 176 (1997).Google Scholar
[3] Bouzidi, L., Pierron-Bohnes, V., Haemmerlè, O., Bouillet-Ulhaq, C. and Cadeville, M.C., Thin Solid Films, in press (1998).Google Scholar
[4] Harp, G. R., Weller, D., Rabedeau, T. A., Farrow, R. F. C. and Toney, M. F., Phys. Rev. Lett. 71, 2493 (1993).Google Scholar
[5] Maret, M., Cadeville, M.C., Staiger, W., Beaurepaire, E., Poinsot, R. and Herr, A., Thin Solid Films, 275, 224 (1996).Google Scholar
[6] Pierron-Bohnes, V., Maret, M., Bouzidi, L. and Cadeville, M.C., to be published in “Diffusion Mechanisms in Crystalline Materials.”, Mat. Res. Soc. Symp. Proc. (1998).Google Scholar
[7] Gauthier, Y., Surface Review and Letters, 3, 1663 (1996) and references therein.Google Scholar
[8] Lefevre, A. et al. , Philos. Mag. A 63, 471 (1991).Google Scholar
[9] Maret, M., Cadeville, M.C., Herr, A., Poinsot, R. and Beaurepaire, E., submitted to J. Magn. Magn. Mater.Google Scholar
[10] Pearson, W. B., Handbook of lattice spacings and structures of metals, Pergamon Press, New York, 1958 Google Scholar
[11] Flynn, C. P., Phys. Rev. Let., 57, 599 (1986)Google Scholar
[12] Gschneidner, K. A., Solid State Physics,16, 275(1964)Google Scholar
[13] Stoeffier, D. and Gautier, F., in Structural and phase stability of alloys, edited by Moran-Lopez, J. L. et al. , Plenum Press, New York, (1992)Google Scholar
[14] Godowski, P. J., Applied Surface Science 47, 333 (1991)Google Scholar