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MA: Fachverband Magnetismus

MA 18: Poster I : Bio Magn. (1-2); Mag.Imgaging (3-9); Magn. Semiconductors (10-16); Half Metals & Oxides (17-20); Coupl.Phenomena (21-27); Magn. Mat. (28-41); Micro & Nanostr. Magn. Materials (42-61); Micro Magn. (62-64); Surface Magnetism (65-70); Transport Phenomena (71-85)

MA 18.82: Poster

Tuesday, February 26, 2008, 15:15–18:30, Poster E

Current induced diffusion in magnetic tunnel junctions with ultra-thin MgO tunnel barriers — •Patryk Krzysteczko¹, Xinli Kou^1,2, Karsten Rott¹, Andy Thomas¹, and Günter Reiss¹ — ¹Bielefeld University, Universitätsstraße 25, D-33615 Bielefeld — ²Lanzhou University, 73000 Lanzhou, China

We apply high current-pulses (j∼ 10⁶ A/cm²) to thin MgO barriers in a CoFeB/MgO/CoFeB TMR element prepared of magnetron sputtering and subsequent electron beam lithography. The samples are charactarized by a low area resistance (AR∼ 20 Ωµ m²) and a high spin polarization (TMR∼ 100 %). We observe reversible resistance changes when a critical electrical current is applied. Depending on the current polarity, the resistance decreases monotonically or non-monotonically with one or two distinct relaxation times, respectively. These different relaxation processes suggest independent physical mechanisms acting simultaneously inside the TMR element. The physical origin of these effects is discussed.