Regensburg 2000 – wissenschaftliches Programm
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AM: Magnetismus
AM 18: Magnetowiderstand II: Oxide und Tunnelmagnetowiderstand
AM 18.12: Vortrag
Donnerstag, 30. März 2000, 12:15–12:30, H10
Reproducibility of the Switching Behavior of sub-micron Ferromagnetic Tunnel Junctions — •U. K. Klostermann1,2, R. Kinder1,2, S. Zoll2, HAM v. d. Berg2, R. Leuschner3, G. Rupp2, and J. Wecker2 — 1Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg — 2Siemens AG, ZT MF 1, Paul-Gossen-Str. 100, D-91052 Erlangen — 3Infineon Technologies, Paul-Gossen-Str. 100, D-91052 Erlangen
Here we report on the reproducibility of the switching characteristics of sub-micron ferromagnetic tunnel junction, which is considered to be a well promising candidate for non volatile solid state memories (Magnetic Random Access Memories, MRAM).
The magnetic multilayers of the spin tunneling device were grown in a high vacuum sputtering system. The hard reference electrode was either a single Co layer or an artificial antiferromagnet (AAF), e.g. Co/Cu/Co, while the soft detection layer (iron, permalloy) was separated by a thin aluminum oxide tunnel barrier. The definition of the nanostructure was done by electron beam lithography and a subsequent ion milling step. Not only the size but also the shape of the tunnel junctions have been varied. The reproducibility of major and minor loops of the tunneling magnetoresistance was poor for elements in the sub-micrometer range with a single Co reference layer, whereas the AAF provides a more stable system. This shows that likely some magnetostatic coupling and also magnetoelastic effects are of importance for sub-micron elements.