Spin-torque switching and control using chirped AC currents

Guillaume Klughertz, Lazar Friedland, Paul Antoine Hervieux, Giovanni Manfredi

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

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°) with respect to the anisotropy axis. The drive current can be modest (106 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.

Original languageEnglish
Article number415002
JournalJournal of Physics D: Applied Physics
Volume50
Issue number41
DOIs
StatePublished - 15 Sep 2017

Bibliographical note

Publisher Copyright:
© 2017 IOP Publishing Ltd.

Keywords

  • autoresonance
  • magnetization dynamics
  • spin torque transfer
  • spin-torque nano-oscillators

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