Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 7: Spin-Dynamics/ Spin-Torque II
MA 7.2: Vortrag
Montag, 23. März 2009, 15:30–15:45, HSZ 04
Current-induced magnetization dynamics in single magnetic-layer nanopillars — •Sarah Fahrendorf1,3, Nicolas Müsgens1,3, Marc Weidenbach1,3, Matthias Bückins2,3, Joachim Mayer2,3, Bernd Beschoten1,3, and Gernot Güntherodt1,3 — 1Physics Institute IIA, RWTH Aachen University, Aachen, Germany — 2Central Facility for Electron Microscopy, RWTH Aachen University, Aachen, Germany — 3JARA-Fundamentals of Future Information Technology
The current-induced generation of spin waves in Cu/Co/Cu single magnetic-layer
nanopillar devices with asymmetric Cu leads is investigated by means of transport
and microwave probes at room temperature. The magnetic field is applied
perpendicular to the Co layer. Molecular beam epitaxy is used to deposit the thin film
stack in prefabricated nanostencil masks with lateral dimensions below 100 nm.
Magneto-transport measurements show peaks and dips in the differential resistance for high negative current densities j < −2·108 A/cm2 and external magnetic fields above |1.5 kOe|. (Negative current is defined as electron flow from the thin to the thick copper layer.) These nonhysteretic features are due to a continuous change of resistance and can be correlated with measured spin wave excitations. At low fields we measure excitation frequencies which decrease with increasing absolute current, whereas the opposite dependence is found at higher fields.
Work supported by DFG through SPP1133