Regensburg 2004 – wissenschaftliches Programm
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MA: Magnetismus
MA 16: Magn. Kopplungsph
änomene
MA 16.7: Vortrag
Mittwoch, 10. März 2004, 16:45–17:00, H22
90∘ coupling in (Fe/Cr/Fe)AFM/Cr/Fe system epitaxially grown on GaAs(001) — •M. Przybylski1, J. Grabowski1, W. Wulfhekel1, M. Rams2, and J. Kirschner1 — 1Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle — 2Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow, Poland
Single-crystalline (Fe/Cr/Fe)AFM/Cr/Fe structures were epitaxially grown on atomically flat GaAs(001). The (Fe/Cr/Fe)AFM layered antiferromagnet shows an easy-axis of magnetization along the [110] direction which is due to the uniaxial anisotropy existing in the bcc-Fe(001) films grown on GaAs(001). Choosing the same thickness of the antiferromagnetically (AFM) coupled two Fe layers, the net magnetization of the (Fe/Cr/Fe)AFM is balanced to zero. This holds in particular up to a spin-flop transition when the field is applied along the [110] direction. Adding a second Cr and a third Fe layer of such thicknesses that the top Fe layer is weakly magnetically coupled to the bottom (Fe/Cr/Fe)AFM structure, low field MOKE and SQUID magnetization loops show reversal in only the top Fe layer of the (Fe/Cr/Fe)AFM/Cr/Fe structures. In particular, a strong increase of coercivity (by factor of 12) is found at low temperatures. 90∘ coupling is detected which affects the minor loops measured along the [-110] and [100] direction.