Regensburg 2002 – wissenschaftliches Programm
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MA: Magnetismus
MA 7: Spinabhängige Transportphänomene II
MA 7.5: Vortrag
Dienstag, 12. März 2002, 10:30–10:45, H22
Magnetic stability of tunnel junctions — •R. Kinder1,2, L. Bär1, G. Rupp1, G. Bayreuther2, and J. Wecker1 — 1Siemens AG, CT MM 1, Paul-Gossen-Str. 100, D-91052 Erlangen — 2Department of Physics, University of Regensburg, Universitätsstr. 31, D-93040 Regensburg
Magnetic tunnel junctions (MTJ) have been intensively studied during the last years, because of their possible use in nonvolatile memories. In a memory device the elements will be arranged in a matrix; the switching process of the elements will be achieved by two crossed fields generated by currents through the top and bottom lines. It is possible to chose the two fields in a way that only the selected element at the crossing points of the two lines is switched.
A point of special interest is the behavior not selected elements which are exposed to a significant field during the writing process. It has to be ensured that the remanent magnetic state of this elements is not changed by the applied fields.
Here we show measurements on the switching behavior of elements for switching with one field and two crossed fields. For increasing hard axis fields a decrease of the switching field in easy axis direction is observed, like expected by the Stoner-Wohlfarth theory. We also present data on the stability of the remanent state under the influence of a small field in easy and hard axis direction. It is observed that the stability is influenced by the shape and the shape anisotropy of the particle. These measurements were done additionally with pulsed fields with a high number of cycles.