Hostname: page-component-848d4c4894-xm8r8 Total loading time: 0 Render date: 2024-06-16T10:56:26.006Z Has data issue: false hasContentIssue false
  • English
  • Français

Respective Roles of Surface, Grain Boundary and Volume Diffusions in Driving Structural, Microstructural and Magnetic Properties of MBE Alloy Thin Films

Published online by Cambridge University Press:  10 February 2011

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

Abstract

The co-deposition of two metals using a molecular beam epitaxy (MBE) technique at various growth temperatures (TG) yields single-crystal alloy thin films with a columnar microstructure whose structural and magnetic properties can be different from those of the corresponding equilibrium bulk alloys. A general overview of results obtained in hcp Co-Ru and hcp or fcc Co-Pt thin films grown on a hcp (0002) substrate will be presented. Around the A 3B composition (A = Co, B = Ru or Pt) the films display a composition modulation along the growth direction whose amplitude is strongly dependent of TG passing through a maximum at respectively 600 and 650 K. This long range order (LRO) that does not exist in equilibrium phases is explained as resulting from the competition between two phenomena occurring simultaneously during the growth process: a surface effect driven by surface interactions and surface diffusion that tends to enrich the surface layer in one element (Co, Ru or Pt segregation) and a bulk effect driven by bulk interactions and bulk diffusion that tends to restore the bulk equilibrium phase when the bulk diffusion becomes efficient during the growth time. A thermally activated model that takes into account both surface and bulk diffusion during the growth time reproduces quite satisfactorily the TG dependencies of the LRO in Co3Ru and Co3Pt as well as that of the uniaxial magnetic anisotropy in CoPt3.

At high TG ( > 800 K) or after ex situ anneals, the diffusion of the Ru buffer through the grain boundaries of the columnar microstructure, that occurs before the inside grain diffusion, isolates the columns magnetically and is thought to be responsible of the large observed coercive field and of a substantial modification of the magnetic domain shapes.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 527: Symposium Z – Diffusion Mechanisms in Crystalline Materials , 1998 , 279
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

REFERENCES

[1] Pierron-Bohnes, V., Ringelstein, N., Michel, A., Boukari, S., Bouzidi, L., Persat, N., Beaurepaire, E., Hehn, M., Muller, D., Cadeville, M.C., J Magn Magn Mater, 165 176 (1997).Google Scholar
[2] Bouzidi, L., Pierron-Bohnes, V., Haemmerlé, O., Bouillet-Ulhaq, C. and Cadeville, M.C., Thin Solid Films, in press (1998).Google Scholar
[3] Maret, M., Cadeville, M.C., Staiger, W., Beaurepaire, E., Poinsot, R. and Herr, A., Thin solid films, 275 224 (1996).Google Scholar
[4] Maret, M., Cadeville, M.C., Poinsot, R., Herr, A., Beaurepaire, E. and Monnier, C., JMMM, 166, 45–52 (1997)Google Scholar
[5] Harp, G. R., Weller, D., Rabedeau, T. A., Farrow, R. F. C. and Toney, M. F., Phys. Rev. Lett. 71 2493 (1993).Google Scholar
[6] Rooney, P.W., Shapiro, A.L., Tran, M.Q. and Hellman, F., Phys Rev Lett, 75 1843 (1995).Google Scholar
[7] Bouzidi, L., Maret, M., Pierron-Bohnes, V. and Cadeville, M.C., Symposium AA, this conferenceGoogle Scholar
[8] Meneghini, C., Maret, M., Cadeville, M.C. and Hazemann, J.L., J. Physique IV FRANCE 7 C2, 1115 (1997).Google Scholar
[9] Gauthier, Y., Surface Review and Letters, 3 1663 (1996) and references therein.Google Scholar
[10] Gehanno, V., Marty, A., Gilles, B. and Samson, Y., Phys. Rev. B, 55 12552 (1997).Google Scholar
[11] Dahmani, C.E., Cadeville, M.C. and Pierron-Bohnes, V., Acta Metall., 3 369 (1985).Google Scholar
[12] Mikkola, D.E. and Cohen, J.B., in Local atomic Arrangements Studied by X-Ray Diffraction, pp. 289–337, Gordon and Breach New York (1966).Google Scholar
[13] Smithells, C.J., in: Metal reference Handbook, Plenum press New York p.644 (1967).Google Scholar
[14] Iijima, Y., Taguchi, O. and Hirano, K., Trans. JIM, 21 366 (1980).Google Scholar
[15] Lefevre, A. et al., Philos. Mag. A 63 471 (1991).Google Scholar
[16] Godowski, P.J., Applied surface Science, 47 333 (1991).Google Scholar
[17] Leroux, C., Cadeville, M.C., Pierron-Bohnes, V., Inden, G. and Hinz, F., J. Phys. F, 18 369 (1988).Google Scholar
[18] Lodder, J.C., in: Magnetic Microstructures of Perpendicular Magnetic Recording Media, MRS Bulletin (October 1995) p. 59 and references therein.Google Scholar