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arXiv · 1610.01819

Spin-torque switching and control using chirped oscillating currents

Guillaume Klughertz·Lazar Friedland·Paul-Antoine Hervieux·Giovanni Manfredi
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Abstract

We propose to use oscillating spin currents with slowly varying frequency (chirp) to manipulate and control the magnetization dynamics in a nanomagnet. By recasting the Landau-Lifshitz-Slonczewski equation in a quantum-like two-level formalism, we show that a chirped spin current polarized in the direction normal to the anisotropy axis can induce a stable precession of the magnetic moment at any angle (up to $90^\circ$) with respect to the anisotropy axis. The drive current can be modest ($10^6\,\rm A/cm^2$ or lower) provided the chirp rate is sufficiently slow. The induced precession is stable against thermal noise, even for small nano-objects at room temperature. Complete reversal of the magnetization can be achieved by adding a small external magnetic field antiparallel to the easy axis. Alternatively, a combination of chirped ac and dc currents with different polarization directions can also be used to trigger the reversal.

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Guillaume Klughertz, Lazar Friedland, Paul-Antoine Hervieux, Giovanni Manfredi. 2016-10-06. Spin-torque switching and control using chirped oscillating currents. https://doi.org/10.1088/1361-6463%2Faa860b

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