Berlin 2005 – scientific programme
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MA: Magnetismus
MA 17: Spinabh
ängiger Transport II
MA 17.1: Talk
Monday, March 7, 2005, 10:30–10:45, TU H1012
Influence of domain wall stray fields on the magnetization reversal of an FeNi/Al2O3/Co tunnel junction — •K. Fukumoto1, W. Kuch1, J. Vogel2, R. Hertel1, J. Camarero3, S. Pizzini2, F. Romanens2, M. Bonfim2, A. Fontaine2, and J. Kirschner1 — 1Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany — 2Laboratoire Louis Néel, CNRS, 25 avenue des Martyrs, B. P. 166, F-38042 Grenoble Cedex 9, France — 3Dpto. Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
Understanding and controlling the magnetization reversal of magnetic trilayers in which two ferromagnetic layers (FM) are coupled across a non-magnetic spacer layer is an important issue for the investigation of many interesting phenomena as well as for applications. We used a novel combination of photoelectron emission microscopy, x-ray magnetic circular dichroism and stroboscopic pump-probe technique, in which nanosecond-short magnetic field pulses (the pump) are synchronised to x-ray pulses from BESSY (the probe), to study the magnetization reversal dynamics of a permalloy layer in a FeNi/Al2O3/Co magnetic tunnel junction with temporal, layer, and spatial resolution. We observe that the stray field from domain walls in the magnetically harder Co layer plays an important role in the magnetization reversal of the softer permalloy layer. During the field pulse, magnetic domains in the permalloy layer nucleate preferentially above domain walls in the Co layer. This is compared to micromagnetic simulations of a hard–soft trilayer system.