Regensburg 1998 – scientific programme
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AM: Magnetismus
AM 11: Postersitzung
AM 11.46: Poster
Tuesday, March 24, 1998, 16:15–20:00, B
Spin tunneling in Co/Al-Al2O3/NiFe Junctions — •E. Girgis, P. Rottl"ander, H. Kohlstedt, J. Schelten, and P. Gruenberg — Institute of Thin Film and Ion Technology & Institute of Solid State Research, Forschungszentrum J"ulich GmbH, 52425 J"ulich
Ferromagnetic tunnel junctions with Al barriers which were oxidized in air or in oxygen plasma were fabricated by dc and rf sputter deposition. Optical lithography and ion beam etching were used to define junction areas of different sizes between 1x1 and 100x100 µm. The magnetic tunneling effect has been investigated for Co / Al-Al2O3 / NiFe in order to clarify the relationship between magnetoresistance and the barrier thickness. The tunneling current between the two magnetic layers depends on the relative orientation of the magnetic moments of the two layers which can be changed by applying external magnetic fields. The current-voltage characteristics ΔR/R vs. B magnetoresistance were measured. The magnetic properties were measured by MOKE. The best magnetoresistance results were so far 6% at 300 K. These devices can be used for magnetic sensors and on-volatile memory cell applications.