Regensburg 2013 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 32: Focus Session: Spin Current Devices

MA 32.5: Topical Talk

Donnerstag, 14. März 2013, 11:30–12:00, H10

Current driven domain wall dynamics controlled by proximity induced interface magnetization — •Stuart Parkin — IBM Almaden Research Center, San Jose, California, USA

Ultra-thin perpendicularly magnetized nanowires are the ideal medium for high-density memory and logic devices based on magnetic domain walls. Recently it has been reported that domain walls can be driven by current at very high speed in such nanowires. The high velocity and the direction of motion of the domain walls are inconsistent with conventional theories based on transfer of spin angular momentum from the current. Here we show in nanowires formed from atomically thin Co and Ni layers that interfaces with specific metal layers control both the speed and direction of the domain walls. These layers are formed from non-magnetic metals, namely Pt, Pd and Ir, which become magnetic in proximity to strong ferromagnets. When the induced moment is suppressed by the insertion of atomically thin Au layers the domain walls are considerably slowed. We show that the mechanism driving the domain walls derives from the intertwined phenomena of spin Hall currents in the non-magnetic layers and a Dzialoshinskii-Moriya interaction at the cobalt- non-magnetic interface that fixes the chirality of the domain walls.