Europhys. Lett.
Volume 68, Number 3, November 2004
Page(s) 460 - 466
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 09 October 2004
Europhys. Lett., 68 (3), pp. 460-466 (2004)
DOI: 10.1209/epl/i2004-10213-7

Creep motion of a magnetic wall: Avalanche size divergence

V. Repain1, 2, M. Bauer1, J.-P. Jamet1, J. Ferré1, A. Mougin1, C. Chappert3 and H. Bernas4

1  Laboratoire de Physique des Solides, Université Paris 11, UMR CNRS 8502 Bât. 510, Centre Universitaire - 91405 Orsay Cedex, France
2  Matériaux et Phénomènes Quantiques, Université Paris 7, FDR CNRS 2437 2 place Jussieu, 75251 Paris Cedex, France
3  Institut d'Electronique Fondamentale, Université Paris 11, CNRS, UMR CNRS 8622 Bât. 220, Centre Universitaire - 91405 Orsay Cedex, France
4  Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse, Université Paris 11 CNRS, UMR CNRS 8609, Bât. 108, Centre Universitaire - 91405 Orsay Cedex, France

received 28 June 2004; accepted in final form 6 September 2004
published online 9 October 2004

The motion of a magnetic domain wall in a $\chem{He}$-ion-irradiated $\chem{Pt/Co}$(0.5 $\un{nm}$)/ $\chem{Pt}$ ultrathin film was studied in low applied magnetic fields. The field dependence of the wall velocity displays a creep behaviour, consistently with a critical slowing-down when the field tends to zero. We also show that domain wall motion is induced by large spin reversal avalanches and that the energy barrier increase is directly linked to that of the avalanche size. This observation is in excellent agreement with the theory of elastic manifolds moving in a weakly disordered medium.

75.60.Jk - Magnetization reversal mechanisms.
75.70.-i - Magnetic properties of thin films, surfaces, and interfaces.
78.20.Ls - Magnetooptical effects.

© EDP Sciences 2004