Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-27T01:33:52.107Z Has data issue: false hasContentIssue false

Oscillatory Indirect Coupling Between Perpendicularly Magnetized Co Monolayers Through Cu (111)

Published online by Cambridge University Press:  03 September 2012

Ulrich Gradmann
Affiliation:
Physikalisches Institut, Technische Universität Clausthal, D 3392 Clausthal-Zellerfeld, Germany
Hans-Joachim Elmers
Affiliation:
Physikalisches Institut, Technische Universität Clausthal, D 3392 Clausthal-Zellerfeld, Germany
Juergen Kohlhepp
Affiliation:
Physikalisches Institut, Technische Universität Clausthal, D 3392 Clausthal-Zellerfeld, Germany
Get access

Abstract

Co-Monolayers, prepared by MBE on Cu (111) -surfaces at room temperature and covered by Cu, are ferromagnetic with a Curie-temperature of about 430 K. They are magnetized perpendicularly because of a strong perpendicular magnetic surface anisotropy of the Cu/Co (111) -interface. They provide a remarkably good representation of the 2-dimensional Ising Model. The indirect coupling between these perpendicularly magnetized ferromagnetic monolayers was investigated using samples of type Cu (111) /lCo/DçuCu/lCo/Cu, containing Co/Cu/Co-trilayers composed of Co-Monolayers and a spacer consisting of DCu atomic layers of Cu (111). Torsion oscillation magnetometry of these samples showed clearly a coupling between the monolayers with an oscillatory dependence on DCu. The amplitude of the oscillation is strongly reduced if the coupled Co-films consist of 5 ML instead of 1 M.L. The present controversy on the presence or absence of antiferromagnetic and oscillatory indirect coupling in the Co/Cu (111) -system is discussed in the light of these experiments. The discussion shows that the oscillatory coupling is an intrinsic property of ideal (111)-structures, and can be understood by the RKKY-type theory of indirect coupling between ferromagnetic Monolayers. The usual application of this theory to the coupling between thicker films is justified. However, in the fcc (111) -system there is apparently a specific barrier against complete coalescence, resulting in a tendency to retain holes and channels in the Cu-spacer. This tendency is stronger in flat single-crystal samples than in sputtered films with high densities of atomic steps. Apparently, this results in competing ferromagnetic hole coupling which may more or less completely obscure the intrinsic oscillatory coupling, preferentially in samples grown on extremely flat single crystal surfaces.

Type
Research Article
Copyright
Copyright © Materials Research Society 1993

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] Kittel, C. in Solid State Physics, ed. Seitz, F., Turnbull, D. and Ehrenreich, H., New York 1968, Vol 22, p. 1 Google Scholar
[2] Boyce, J.B. and Slichter, C.P., Phys. Rev. B 13, 379 (1976)Google Scholar
[3] Walker, L.R. and Wernstedt, R.E., Phys. Rev. B 22, 3816 (1980)Google Scholar
[4] Parkin, S.S.P., More, N. and Roche, K.P., Phys. Rev. Lett. 64, 2304 (1990)Google Scholar
[5] Unguris, J., Celotta, R.J. and Pierce, D.T., Phys. Rev. Lett. 67, 140 (1991)Google Scholar
[6] Fuβ, A., Demokritov, S., Grünberg, P. and Zinn, W., J. Magn. Magn. Mat. 103. L221 (1992)Google Scholar
[7] Bruno, P. and C:. Chappert, Phys. Rev. Lett. 67, 1602 (1991)Google Scholar
[8] Xiao, J.Q., Jiang, J.S. and Chien, C.L., Phys. Rev. Lett. 68, 3749 (1992)Google Scholar
[9] Parkin, S.S.P., Bhadra, R. and Roche, K.P., Phys. Rev. Lett. 66, 2152 (1991)Google Scholar
[10] Mosca, D.H., Petroff, F., Fert, A., Schroeder, P.A., Pratt, W.P. Jr and Laloee, R., J. Magn. Magn. Mat. 94, L1 (1991)Google Scholar
[11] Cebollada, A., Martinez, J.L., Gallego, J.M., de Miguel, J.J., Miranda, R., Ferrer, S., Fillion, G. and Rebouillat, J.P., Phys. Rev. B 39, 9726 (1989)Google Scholar
[12] Pescia, D., Kerkmann, D., Schumann, F. and Gudat, W., Z. Phys. B 78, 475 (1990)Google Scholar
[13] Johnson, M.T., Purcell, S.T., McGee, N.W.E, Coehoorn, R., aan de Stegge, J. and Hoving, W., Phys. Rev. Lett. 68, 2688 (1992)Google Scholar
[14] Bennett, W.R., Schwarzacherand, W. Egelhoff, W.F. Jr, Phys. Rev. Lett. 65, 3169 (1990)Google Scholar
[15] Egelhoff, W.F. Jr and Kief, M.T., Phys. Rev. B 45, 7795 (1992)Google Scholar
[16] Johnson, M.T., Coehoorn, R., de Vries, J.J., Mc Gee, N.W.E., aan de Stegge, J. and Bloemen, P.J.H., Phys. Rev. Lett. 69, 969 (1992)Google Scholar
[17] Kohlhepp, J., Cordes, S., Elmers, H.J. and Gradmann, U., J. Magn. Magn. Mat. 111. L 231 (1992)Google Scholar
[18] Kohlhepp, J., Elmers, H.J., Cordes, S. and Gradmann, U., Phys. Rev. B 45, 12287 (1992)Google Scholar
[19] Gradmann, U. and Müller, J., Z. angew. Physik 30, 87 (1970)Google Scholar
[20] Gradmann, U. and Müller, J., Czech. J. Physics B 20, 553 (1971)Google Scholar
[21] Gradmann, U. and Müller, J., phys. stat. sol. 27, 313 (1968)Google Scholar
[22] Gradmann, U., J. Appl. Phys. 40, 1182 (1969)Google Scholar
[23] Gradmann, U., Appl. Phys. 3, 161 (1974)Google Scholar
[24] Gradmann, U., Kümmerle, W. and Tham, R., Appl. Phys. 10, 219 (1976)Google Scholar
[25] Kohlhepp, J., Elmers, H.J. and Gradmann, U., J. Magn. Magn. Mat., in the pressGoogle Scholar
[26] Gradmann, U., Ann. Phys. (Leipzig) 17, 91 (1966)Google Scholar
[27] Pashley, D.W., Advan. Phys. 14, 327 (1965)Google Scholar
[28] Matthews, J.W., in Physics of Thin Films, ed. Hass, G. and Thun, R., Vol 4, p 137 (1967)Google Scholar
[29] Brodde, A. and Neddermeyer, H., Ultramicroscopy 42–44. 556 (1992)Google Scholar
[30] Greig, D-, Hall, M.J., Hammond, C., Hickey, B.J., Ho, H.P., Howson, M. A., Walker, M.J., Wiser, N. and Wright, D.G., J. Magn. Magn. Mat. 110, L 239 (1992)Google Scholar
[31] Renard, J.P., Beauvillain, P., Dupas, C., Le Dang, K., Vélu, E., Marlière, C. and Renard, D., J. Magn. Magn. Mat. 115, L 147 (1992)Google Scholar
[32] Dupas, C., Kolb, E., Le Dang, K., Renard, J.P., Veillet, P. and Vélu, E., preprint 1993 Google Scholar
[33] Schreyer, A., Bröhl, K., Ankner, J.F., Zeidler, Th., Bödeker, P., Metoki, N., Maj krzak, C.F. and Zabel, H., preprint 1993 Google Scholar
[34] Pinkvos, H., private communicationGoogle Scholar
[35] Pinkvos, H., Poppa, H., Bauer, E. and Hurst, J., Ultramicroscopy 47, 339. (1992)Google Scholar