Regensburg 2007 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 10: Layers with Magnetic Properties
DS 10.1: Vortrag
Montag, 26. März 2007, 17:15–17:30, H34
Thermal stability of Py/Cu and Co/Cu giant magnetoresistance (GMR) systems — •Vitaliy Vovk1, Guido Schmitz1, and Andreas Hütten2 — 1Institute of material physics, WWU Münster, Münster, Germany — 2Institute of nanotechnology, Forschungszentrum Karlsruhe, Karlsruhe, Germany
The long-term thermal stability in thin film functional materials often becomes a critical restriction regarding the technical application. GMR multilayer (ML) systems (Co/Cu and Py/Cu) are studied in this aspect since their automotive application requires operation in hot environments.
Tomographic atom probe analysis of Py/Cu system [1] conducted in our group has shown the minor broadening of the layer interfaces to be the most probable reason for the GMR degradation. Comparable results are observed in Co/Cu system using wide angle atom probe tomography (WATAP), though the systems have rather different thermodynamics. Besides the atomic transport, another important transformation takes place at elevated temperatures. The broad <111>- changes to sharp <200>-texture during the recrystallization process. It is shown that this texture reorientation is due to the anisotropic energy terms competition in the multilayer system. Since the RKKY coupling length depends among other parameters on the crystallographic orientation of the system, the thermal stability of the GMR effect can be significantly improved by the control of texture reorientation.
[1] C. Ene, G. Schmitz, R. Kirchheim, A. Hütten, Acta Materialia 53, 3383, 2005.