Regensburg 2010 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 33: Poster II
MA 33.65: Poster
Freitag, 26. März 2010, 11:00–14:00, Poster B1
A sensor layer to magnify the magnetic vortex core — •Edward Prabu Amaladass1, Vitalij Sackmann1, Manfred Fähnle1, Markus Weigand1, Michael Curcic1, Hermann Stoll1, Joachim Albrecht2, Bartel Van Waeyenberge3, Tolek Tyliszckak4, Georg Woltersdorf5, and Gisela Schütz1 — 1MPI für Metallforschung, Stuttgart, Germany — 2Hochschule Aalen, Germany — 3Ghent University, Belgium — 4ALS, LBNL Berkeley, CA, USA — 5Universität Regensburg, Germany
Vortex core switching could be achieved by dynamic in-plane Oersted fields or spin torque excitations. Since the dimension of the vortex core is only about 10 - 20 nm in diameter, reading out the magnetization direction of the vortex core has been a hurdle for technological applications. We have found that a GdFe layer can act as a sensor for vortex core switching by magnifying significantly the lateral size of the out-of-plane magnetization. A GdFe layer, showing perpendicular anisotropy and coercivity fields of the order of mT, was used in a Permalloy (PY) - Al - GdFe multilayer system. By magnetic X-ray microscopy and by taking advantage of the element specificity of XMCD, the switching of the out-of-plane magnetization is observed at the Ni L3 and Gd M5 absorption edges. It could be demonstrated that by application of a magnetic RF burst of adequate amplitude and length the vortex core polarization in the PY layer is reversed. Consequently, the magnetization of the whole GdFe cover layer is also switched by the stray field of the tiny PY vortex core. This enabled us to detect the vortex core polarization by magneto-optical Kerr microscopy for the first time.