Direct observation of Oersted-field-induced magnetization dynamics in magnetic nanowires

Vojtech Uhlîr (1, 2) , Stefania Pizzini (3) , Nicolas Rougemaille (3) , Vincent Cros (4) , Erika Jimenez (5) , Laurent Ranno (3) , Olivier Fruchart (3) , Michal Urbanek (2) , Gilles Gaudin (6) , Julio Camarero (5) , Carsten Tieg (7) , Fausto Sirotti (8) , Jan Vogel (3)

1 NEEL - Institut Néel
2 Institute of Physical Engineering
3 NEEL - MNM - Micro et NanoMagnétisme
4 Laboratoire Albert Fert (ex-UMPhy Unité mixte de physique CNRS/Thales)
5 FMC - Departamento de Fisica de la Materia Condensada [Madrid]
6 SPINTEC - SPINtronique et TEchnologie des Composants
7 ESRF - European Synchrotron Radiation Facility
8 SSOLEIL - Synchrotron SOLEIL

We have used time-resolved x-ray photoemission electron microscopy to investigate the magnetization dynamics induced by nanosecond current pulses in NiFe/Cu/Co nanowires. The Oersted magnetic field present during the current pulses induces a large tilt of the NiFe magnetization, transverse to the wires. Spin-wave-like oscillations of the NiFe magnetization are also observed and attributed to precessional motion about the effective field. Our results clearly show that both the quasi-static and dynamic effects of the Oersted field have to be taken into account when interpreting current-induced domain wall motion in multilayered nanowires. This internal, transverse magnetic field may contribute to the increased efficiency of current-induced domain wall motion observed in NiFe/Cu/Co nanowires.

Mots clés: magnetic nanowires; spin-valves; spin torque; magnetization dynamics; time-resolved PEEM

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Vojtech Uhlîr, Stefania Pizzini, Nicolas Rougemaille, Vincent Cros, Erika Jimenez, et al.. Direct observation of Oersted-field-induced magnetization dynamics in magnetic nanowires. 2010. ⟨hal-00453804v1⟩