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Magnetic vortex core reversal by rotating magnetic fields generated on micrometer length scales

✍ Scribed by Michael Curcic; Hermann Stoll; Markus Weigand; Vitalij Sackmann; Patrick Juellig; Matthias Kammerer; Matthias Noske; Markus Sproll; Bartel Van Waeyenberge; Arne Vansteenkiste; Georg Woltersdorf; Tolek Tyliszczak; Gisela Schütz


Publisher
John Wiley and Sons
Year
2011
Tongue
English
Weight
513 KB
Volume
248
Category
Article
ISSN
0370-1972

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✦ Synopsis


Abstract

Unidirectional switching of the magnetic vortex core can be achieved in micron‐sized ferromagnetic platelets by excitation of the gyrotropic mode of the vortex structure with in‐plane rotating magnetic fields. Circulating fields with a switchable sense of rotation (clockwise, CW or counter clockwise, CCW) have been generated on a micrometer length scale at frequencies up to 1 GHz by two orthogonal electric RF currents with 90° phase shift flowing through crossed but not isolated striplines. Decoupling of these currents is realized by balanced symmetric RF sources. The amplitudes of the rotating magnetic fields and their spatial distributions are calculated and the stripline geometry is discussed. By taking advantage of this technique, unidirectional vortex core reversal by excitation with CW or CCW rotating magnetic fields has been observed by time resolved scanning transmission X‐ray microscopy. An area with reversed magnetization, the “dip,” was observed near the vortex core before vortex core reversal.