Regensburg 2007 – scientific programme

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MA: Fachverband Magnetismus

MA 19: Spin-Dynamics/Switching I

MA 19.7: Talk

Wednesday, March 28, 2007, 16:45–17:00, H23

Current-Induced Excitations in Single Ferromagnetic Layer Nanopillars — •Malte Scherff, Anne Parge, Tore Niermann, Michael Seibt, and Markus Münzenberg — IV. Phys. Inst., Universität Göttingen

So far the focus of angular momentum transfer studies has usually been put on ferromagnet/ normal magnet/ ferromagnet trilayer junctions. Our work also includes transport experiments in junctions with only a single ferromagnetic layer.

All experiments have been performed on nanopillars with a diameter of ~80 nm,which are fabricated in a simplified one step process: Holes are created into a thin PMMA film by e-beam lithography and filled with different metal layers by evaporation. The remaining PMMA serves as an insulating template between the Au bottom- and the Cu top-contact.

To improve the preparation parameters, structural analysis has been done by simple cross sectional views as well as accurate TEM measurements of lamella-samples prepared by focused ion beam.

The transport properties 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 anomaly changes of resistance were observed in trilayers (up to 3%) and single layers (up to 1.5%). They are related to dynamic excitations and static changes in magnetic configuration, respectively.

This work was supported by DFG, SPP 1133.