Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 18: Poster I : Bio Magn. (1-2); Mag.Imgaging (3-9); Magn. Semiconductors (10-16); Half Metals & Oxides (17-20); Coupl.Phenomena (21-27); Magn. Mat. (28-41); Micro & Nanostr. Magn. Materials (42-61); Micro Magn. (62-64); Surface Magnetism (65-70); Transport Phenomena (71-85)

MA 18.71: Poster

Dienstag, 26. Februar 2008, 15:15–18:30, Poster E

Current induced domain wall motion in perpendicularly magnetized wires — •Johannes Kimling, Olivier Boulle, Mathias Kläui, and Ulrich Rüdiger — Fachbereich Physik, Universität Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany

The recent discovery that a spin polarized current can move a domain wall (DW) through a transfer of spin angular momentum opens a new path to manipulating magnetization without any external magnetic field. So far, current induced DW motion (CIDM) has been experimentally investigated in details for in-plane magnetized wires with a large DW width (≥100 nm) where spin transfer is expected to occur in the “adiabatic limit". Here, we will present experiments on (Pt/Co)_n thin films with perpendicular magnetic anisotropy in which a very narrow DW is expected (width ≈10 nm). This allows the investigation of the non adiabatic part of the spin transfer torque, a key parameter in CIDM, which is expected to be larger for narrower DWs. The CIDM was studied in (Pt/Co)_n films patterned in 200-500 nm wide nanowires. Using the extraordinary Hall effect, we have observed small displacements of a domain wall pinned in the Hall cross induced by current pulses of the order of 10¹¹ A/m² at low field, in agreement with previous works. In order to correct for the significant temperature rise caused by the Joule heating while injecting current pulses, a systematic study of current induced depinning under various field and temperature has been carried out. By taking into account the role of the Joule heating in CIDM, this allows a true evaluation of the efficiency of the spin transfer in this material.