Regensburg 2004 – wissenschaftliches Programm
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MA: Magnetismus
MA 16: Magn. Kopplungsph
änomene
MA 16.6: Vortrag
Mittwoch, 10. März 2004, 16:30–16:45, H22
Two dimensional recrystallization, the key towards temperature stable Co/Cu multilayers — •Sonja Heitmann1, Andreas Hütten1, Guido Schmitz2, and Günter Reiss1 — 1Universität Bielefeld, Fakultät für Physik, Universitätsstraße 25, 33615 Bielefeld — 2Westfälische Wilhelms-Universität Münster, Institut für Materialphysik, Wilhelm-Klemm-Straße 10, 48149 Münster
One of the major concerns for automotive sensor application is the temperature stability at elevated temperatures. The breakdown of the GMR-effect amplitude of Co/Cu multilayers beyond 250∘C [1] and 350∘C [2] for Co layer thickness of 1nm and 1.5nm, respectively, reveals the weakness of conventionally prepared multilayer systems.
However, the objective of this talk is to demonstrate that alternatively prepared Cu/Co multilayers are very much able to withstand high temperature without a degradation of the GMR-effect amplitude. The key is to utilize a two dimensional recrystallization process at sufficient high temperatures around 500∘C. It will be shown that these multilayers are stable upon subsequent annealing at temperatrures between 400∘C and 500∘C. The microstructural evolution will be linked to results concerning transport, magnetic and microstructure measurements and will reveal the interplay of layer quality, grain size and orientation with crystalline anisotropy, antiferromagnetic coupling and GMR.