Dresden 2006 – scientific programme

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MA: Magnetismus

MA 15: Spin-Dependent Transport Phenomena II

MA 15.4: Talk

Tuesday, March 28, 2006, 11:00–11:15, HSZ 103

Current-Induced Excitations in Single Ferromagnetic Layer Nanopillars — •A. Parge and M. Münzenberg — IV. Phys. Inst., Universität Göttingen

Angular momentum transfer studies in magnetic nanostructures have mainly been performed on ferromagnet/ normal magnet/ ferromagnet bilayer junctions so far. But due to spin accumulation on either side of a ferromagnet in the cpp geometry, spin wave excitations have also been predicted theoretically and observed experimentally for junctions with only a single ferromagnetic layer.

We used e-beam lithography and evaporation in order to pattern normal metal/ ferromagnet/ normal metal pillars with a diameter of ~100 nm on an Au bottom electrode. PMMA served as an insulating template for these structures. Thus a Cu electrode could be smoothly deposited on top of each structure.

All the experimental results presented were obtained in a four point measurement configuration, where the differential resistance dV/dI was measured by a lock-in technique in an external magnetic field. For sufficiently large DC current densities anomalies in dV/dI were observed. The correlation between these phenomena and spin transfer will be discussed in terms of field and current dependence as well as structural asymmetries.