Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 32: Postersession II: Spinstruct./Phase Trans. (1-10); Spinelectronics (11-15); Thin Films (16 - 36); Particles/Clusters (37-45); Multiferroics (46-54); Spindynamics/Spin Torque (55 - 76); Post Deadlines (77-79)

MA 32.68: Poster

Freitag, 29. Februar 2008, 11:15–14:00, Poster E

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

In this work we would like to present the results of angular momentum transfer studies of ferromagnet/ normal metal/ ferromagnet trilayer junctions with high magnetic fields. Magnetic field sweeps at different temperatures and orientations will be shown and compared with GMR-measurements for consistence.

All experiments have been performed on nanopillars with a diameter of ~100 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.

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(up to 20%). The dynamic and static changes of resistances at fields up to 5T suggest the existence of strong current driven inhomogenious magnetisation with vortex states in the layer system.

Also electrical aging effects of pillars during longer measurement periods are discussed. This work was supported by DFG, SPP 1133.