Dresden 2009 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 40: Poster II: Bio- and Molecular Magnetism (1-9); Magnetic Coupling Phenomena/Exchange Bias (10-15); Magnetic Particlicles and Clusters (16-29); Micro and Nanostructured Magnetic Materials (30-51); Multiferroics (52-64); Spin Injection in Heterostructures (65-67); Spin-Dyn./Spin-Torque (68-93); Spindependent Transport (94-108)

MA 40.106: Poster

Freitag, 27. März 2009, 11:00–14:00, P1A

Inelastic electron tunneling spectroscopy of magnetic tunnel junctions with different electrode designs and barrier materials — •Volker Drewello, Markus Schäfers, Oliver Schebaum, Andy Thomas, and Günter Reiss — Bielefeld University, 33615 Bielefeld, Germany

MgO based magnetic tunnel junctions with up to 230 % tunnel magneto resistance ratio at room temperature and up to 345 % at 13 K are prepared. The lower electrode is either exchange biased or free, while the top electrode is free or an exchanged biased artificial ferrimagnet, respectively. Additionally, a pseudo spin valve (hard soft switching) design with two unpinned electrodes is used. Inelastic electron tunneling spectra for each of these systems show a strong variation of the zero bias anomaly with a reduced peak for some of the junctions. At voltages around 200 mV additional structures are found which are not known from junctions with lower magneto resistance, such as alumina based junctions. We discuss the spectra for the different electrode types and compare our findings with respect to barrier material and magneto resistance ratio.