Berlin 2005 – scientific programme
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MA: Magnetismus
MA 11: FV-internes Symposium ”Applied Magnetism” (Organizers: R. Hilzinger, H. Huneus, J. Wecker)
MA 11.4: Invited Talk
Saturday, March 5, 2005, 10:30–11:00, TU H1028
Magnetic tunnel junctions with different barriers for magnetoelectronic applications — •Theodoros Dimopoulos1, Günter Gieres1, Nils Wiese1, Joachim Wecker1, Juansu Luo2, and Konrad Samwer2 — 1Siemens AG, CT-MM1, Paul-Gossen-Str. 100, 91052 Erlangen — 2I. Physikalische Institut, Universität Göttingen, Tammannstr. 1, 37077 Göttingen
Magnetic tunnel junctions (MTJs) are thin film multilayers comprising of two ferromagnets (FMs) separated by an ultra-thin insulator (tunnel barrier). The current traversing the layered structure depends on the relative orientation of the magnetization of the FMs, giving rise to the tunnel magnetoresistance (TMR) effect. MTJs are expected to be widely used in the near future as sensing elements in various applications (e.g. read-heads, biosensors, automotive, etc.), as well as in the data storage (MRAM) and magnetic logic, with each application imposing its own functional demands.
In this contribution we will focus on the influence of the tunnel barrier on key technological requirements for the MTJs, like the amplitude of the TMR, the resistance-area (RA) product and the switching behavior of the magnetic electrodes. We will specifically discuss Al2O3, Y2O3 and MgO barriers, which are combined with polycrystalline and amorphous magnetic electrodes (e.g. CoFe and CoFeB) in sputter-deposited junctions. The barriers are fabricated using plasma oxidation or reactive sputtering and significant TMR has been measured for every case. Aspects particularly important to applications, like the thermal stability of the different MTJs will also be addressed.