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MA: Magnetismus

MA 25: Hauptvortr
äge Thiaville / Kl
äui

MA 25.1: Hauptvortrag

Donnerstag, 11. März 2004, 14:00–14:30, H10

The physics of magnetic domain wall motion in nanostructures — •André Thiaville, Yoshinobu Nakatani, and Jacques Miltat — CNRS-Uni. Paris-sud, Lab. physique des solides, 91405 Orsay, France

This talk will present our work on the domain wall motion in lithographically defined flat nanowires (thickness 5-10 nm, width 100-200 nm). These structures show domain walls and a dynamic behaviour that are slightly more complex than a one-dimensionnal (1d) solution, whose prototype is the Walker theory for a 1d Bloch wall. First I will discuss field driven propagation (field along the wire axis), which is characterized by the magnetization precession around the applied field. As the wire is too wide to be 1d the so-called Walker breakdown, where a continuous precession of the magnetic moment of the domain wall sets in, is shown to be replaced by the periodic injection and disappearance of an antivortex. This phenomenon is very sensitive to the edges perfection : a wire having rough edges will not undergo this mechanism and hence support fast wall propagation at high fields. Then I will explain our study of the domain wall motion induced by a current in the nanowire, due to the spin-transfer torque. As the form of this torque is not yet fully agreed on, especially in the wire geometry, I will present calculations incorporating different formulations of this torque.