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arXiv · 1509.08752

Field-free magnetization reversal by spin-Hall effect and exchange bias

Arno van den Brink·Guus Vermijs·Aurélie Solignac·Jungwoo Koo·Jurgen T. Kohlhepp·Henk J. M. Swagten·Bert Koopmans
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Abstract

Magnetic random-access memory (MRAM) driven by spin-transfer torque (STT) is a major contender for future memory applications. The energy dissipation involved in writing remains problematic, even with the advent of more efficient perpendicular magnetic anisotropy (PMA) devices. A promising alternative switching mechanism employs spin-orbit torques and the spin-Hall effect (SHE) in particular, but additional symmetry breaking is required to achieve deterministic switching in PMA devices. Currently used methods rely on in-plane magnetic fields or anisotropy gradients, which are not suitable for practical applications. Here, we interface the magnetic layer with an anti-ferromagnetic material. An in-plane exchange bias (EB) is created, and shown to enable field-free SHE-driven magnetization reversal of a perpendicularly magnetized Pt/Co/IrMn structure. Aside from the potential technological implications, our experiment provides additional insight into the local spin structure at the ferromagnetic/anti-ferromagnetic interface.

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Arno van den Brink, Guus Vermijs, Aurélie Solignac, Jungwoo Koo, Jurgen T. Kohlhepp, Henk J. M. Swagten, Bert Koopmans. 2015-09-29. Field-free magnetization reversal by spin-Hall effect and exchange bias. https://doi.org/10.1038/ncomms10854

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