Münster 1999 – wissenschaftliches Programm

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AM: Magnetismus

AM 10: Postersitzung

AM 10.38: Poster

Dienstag, 23. März 1999, 16:15–20:00, F\"urstenberghaus

Different Oxidation Processes for Tunnel Magnetoresistance Devices — •E. Girgis¹, P. Rottl"ander², R. Schmitz¹, H. Kohlstedt¹, J. Schelten¹, and P. Gr"unberg² — ¹Institute for Thin Film and Ion Technology, Research Centre Juelich GmbH, D-52425 J"ulich, Germany — ²Institute for Solid State Research, Research Centre Juelich GmbH, D-52425 J"ulich, Germany

Magnetic tunnel junctions with aluminium oxide barriers were fabricated using sputtering, ion beam etching and optical lithography. The barriers were formed by oxidation in ambient air (ex-situ) and UV light assisted (in-situ) oxidation. Junction with areas from 2.5x10 µm² to 200x400 µm² were produced. The junctions consisted of a 19 nm thick base electrode, a 1.3 nm thick as- deposited aluminium layer(than oxidised) and a 19 nm thick NiFe top electrode. Our best spin-dependent tunnel devices have a magnetoresistance values at room temperature of 19.5% . Current-voltage (I-V) curves and magnetisation measurements (MOKE) were performed. The results showed that the 1.3 nm barrier was pinhole free and the two layers were magnetically decoupled. The possible application of such devices in magneto random access memories (MRAMs) will be discussed.