Spin transfer torques generated by the anomalous Hall effect and anisotropic magnetoresistance

By Tomohiro Taniguchi, Julie Grollier, Mark D. Stiles. 2014

178 citations recorded by the source corpus.

Spin-orbit coupling in ferromagnets gives rise to the anomalous Hall effect and the anisotropic magnetoresistance, both of which can be used to create spin-transfer torques in a similar manner as the spin Hall effect. In this paper we show how these effects can be used to reliably switch perpendicularly magnetized layers and to move domain walls. A drift-diffusion treatment of the anomalous Hall effect and the anisotropic magnetoresistance describes the spin currents that flow in directions perpendicular to the electric field. In systems with two ferromagnetic layers separated by a spacer layer, an in-plane electric field cause spin currents to be injected from one layer into the other, creating spin transfer torques. Unlike the related spin Hall effect in non-magnetic materials, the anomalous Hall effect and the anisotropic magnetoresistance allow control of the orientation of the injected spins, and hence torques, by changing the direction of the magnetization in the injecting layer. The torques on one layer show a rich angular dependence as a function of the orientation of the magnetization in the other layer. The control of the torques afforded by changing the orientation of the magnetization in a fixed layer makes it possible to reliably switch a perpendicularly magnetized free layer. Our calculated critical current densities for a representative CoFe/Cu/FePt structure show that the switching can be efficient for appropriate material choices. Similarly, control of the magnetization direction can drive domain wall motion, as shown for NiFe/Cu/NiFe structures.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/379c064e2c726affea7ae0e0f393ff339b5ec117

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In Atomic and Molecular Physics, and Optics

1. Pietro Gambardella
2. J. Sinova
3. T. Jungwirth
4. A. Manchon
5. I. Miron
6. Kevin Garello
7. A. Thiaville
8. J. Železný

In Condensed Matter Physics

1. J. Sinova
2. T. Jungwirth
3. Pietro Gambardella
4. I. Miron
5. Kevin Garello
6. J. Železný
7. A. Thiaville
8. A. Manchon

Citations in the corpus

• Tilted spin current generated by the collinear antiferromagnet ruthenium dioxide (2021, unknown): “A = AFL cosφ sin 2φ + AFL sinφ sin 2φ + ADL sin 2φ, (5)”
• Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems (2018, background): “A spin current is generated through AHE in the first FM and injected in the second FM, leading to sizable SOT (Bose et al., 2017; Freimuth et al., 2017; Taniguchi et al., 2015) and magnetization switching (Baek et al., 2017), depending on the relative orientation of the two magnetizations.”
• Magnetism, symmetry and spin transport in van der Waals layered systems (2021, unknown): “103 . energy density for a system with perpendicular magnetic anisotropy and an effective field with a component parallel to the anisotropy axis, and the spin-textures that enable these kind of fields. m , magnetization; H , magnetic field strength; J , current .”
• Interface-Induced Phenomena in Magnetism (2016, unknown): “There are currently two proposals for this: (1) use a ferromagnetic layer with tilted magnetization and strong spin-orbit interactions as the source of the spin-orbit torque (replacing the heavy metal layer) [Taniguchi et al., 2015], or (2) use a nonmagnetic single-crystal layer with low crystal sym”