Berlin 2008 – scientific programme

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MA: Fachverband Magnetismus

MA 23: Spinelectronics/ Spininjection in Heterostructures

MA 23.4: Talk

Wednesday, February 27, 2008, 17:30–17:45, H 1028

Magnetic characterization of injector/collector contacts for silicon spintronics — •Daniel Schwarz¹, Theodoros Dimopoulos¹, Thomas Uhrmann¹, Vlado Lazarov², Amit Kohn², Sascha Weyers³, Uwe Paschen³, and Hubert Brückl¹ — ¹Austrian Research Centers GmbH - ARC, Nano System Technologies, Donau-City-Str. 1, 1220 Wien, Austria — ²Department of Materials, University of Oxford, Parks Road, OX1 3PH, U.K. — ³Fraunhofer Gesellschaft, Finkenstr. 61, 45057 Duisburg, Germany

Electrical spin-polarized current injection in Si promises a breakthrough in future spintronic devices. Its efficiency depends strongly on the magnetic properties of the ferromagnetic (FM) contacts used for current injection and detection, commonly including a tunneling barrier between the FM metal and Si. We sputter-deposited rectangular, sub-µm FM contacts, embedded into holes in SiO₂ dielectric prepatterned by optical lithography. As a tunneling barrier we used MgO of thickness between 0 and 2.5nm and a Co₇₀Fe₃₀(2nm)/Ni₈₀Fe₂₀(8nm) bilayer. The antiparallel magnetic state between injector and collector is achieved by tailoring the shape anisotropy. For this, the aspect ratio is varied between 3 and 10. Using magneto-optical Kerr effect, we have studied the dependence of the switching field and its distribution, as a function of the MgO thickness and the aspect ratio, supported by micro-magnetic simulations. Domain structure information is provided by magnetic force microscopy measurements as a function of the magnetic field. The effect of annealing up to 400^∘C is also discussed. We acknowledge support from the EU project EMAC-Strep 017412.