Berlin 2005 – wissenschaftliches Programm

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MA: Magnetismus

MA 23: Spinabh
ängiger Transport III

MA 23.8: Vortrag

Dienstag, 8. März 2005, 12:15–12:30, TU H1028

Local Anisotropic Magnetoresistance Simulations and Measurements — •Markus Bolte, Marcus Steiner, Ulrich Merkt, and Guido Meier — Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstrasse 11, 20355 Hamburg, Germany

Understanding magnetoresistance effects in ferromagnetic nanostructures is prerequisite for the development of magnetoelectronic devices such as read–heads for magnetic storage media, magnetic random access memory cells, and prospective semiconductor/ferromagnet hybrid devices. A spatially resolved picture of magnetoresistance effects allows an accurate prediction and control of the behavior of such devices. We have extended the code of one of the standard micromagnetic simulation frameworks, OOMMF, to simulate the influence of the local anisotropic magnetoresistance (AMR) on the total resistance of micrometer sized permalloy rectangles of varying thicknesses [1]. We compared the results with AMR-measurements done on permalloy (Ni₈₃Fe₁₇) samples with similar geometry. The simulated magnetization configurations and the concomitant magnetoresistances are in good agreement with the magnetic states observed in magnetic-force microscopy and resistance measurements. Finite–element calculations yield the local current density resulting from changes in resistance due to AMR [2].

[1] M. Steiner, C. Pels, M. Barthelmess, M. Bolte, U. Merkt, and G. Meier, to be published.

[2] M. Holz, O. Kronenwerth, and D. Grundler, Phys. Rev. B 67, 195312 (2003).