Berlin 2008 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

MA: Fachverband Magnetismus

MA 19: Spin Dynamics / Spin Torque I

MA 19.14: Vortrag

Mittwoch, 27. Februar 2008, 17:30–17:45, EB 301

Amplification and suppression of magnetic antivortex motion — •André Drews¹, Stellan Bohlens², Benjamin Krüger², Markus Bolte¹, and Guido Meier¹ — ¹Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg — ²I. Institut für Theoretische Physik, Universität Hamburg

We investigate numerically the response of an antivortex to excitation by alternating currents and magnetic fields using micromagnetic simulations. The phase between antivortex deflection and excitation in case of an electrical current depends on the polarization and in case of magnetic field additionally on the chirality. The chirality of an antivortex can be changed by a rotation of the sample with respect to the driving force. The dynamical characteristics of antivortices can be identified with a harmonic oscillator model as it has been recently shown for the vortex state theoretically as well as experimentally. Excitation in a superposition of an electrical current and a magnetic field can lead to an enhancement or to an entire suppression of the amplitude of the antivortex gyration. For example, for an antivortex with positive polarization an angle of 0 or π occurs between magnetic field and current excitation with chiralities c=0 and c=2, respectively. This leads in case of c=0 to an enhancement and in case of c=2 to a quenching of the gyration. In experiments this chirality-dependent amplitude of the gyration can be used to distinguish between current and Oersted field driven antivortex core motion.