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Magnetoresistive Memory with Ultralow Critical Current for Magnetization Switching

Authors

  • Nikolay A. Pertsev,

    Corresponding author
    1. A. F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
    2. Nanoelektronik, Technische Fakultät, Christian-Albrechts-Universität zu Kiel, D-24143 Kiel, Germany
    • A. F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia.
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  • Hermann Kohlstedt

    1. Nanoelektronik, Technische Fakultät, Christian-Albrechts-Universität zu Kiel, D-24143 Kiel, Germany
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Abstract

The data writing and thermal stability of information storage are studied theoretically for a magnetic random access memory (MRAM) composed of a magnetic tunnel junction or multilayer exhibiting giant magnetoresistance. The theoretical analysis focuses on the magnetization switching in the “free” layer of a MRAM cell, which is induced by a spin-polarized current imposing a spin-transfer torque (STT) on the magnetization. It is shown that the writing current in such an STT-MRAM reduces dramatically near a spin reorientation transition (SRT) driven by lattice strains and/or surface magnetic anisotropy and even tends to zero under certain conditions. In particular, at the size-driven SRT in the perpendicular-anisotropy CoFeB-MgO tunnel junctions, the critical current densities for magnetization reorientations between the parallel and antiparallel states are expected to fall to low values of about 1.3 × 105 and −3.3 × 104 A cm−2. Remarkably, STT-MRAMs may combine low writing current with very high thermal stability of information storage (retention over 10 years) even at a high density ≈500 Gbit inch−2.

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