TY - JOUR
T1 - Spin-torque switching and control using chirped AC currents
AU - Klughertz, Guillaume
AU - Friedland, Lazar
AU - Hervieux, Paul Antoine
AU - Manfredi, Giovanni
N1 - Publisher Copyright:
© 2017 IOP Publishing Ltd.
PY - 2017/9/15
Y1 - 2017/9/15
N2 - 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.
AB - 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.
KW - autoresonance
KW - magnetization dynamics
KW - spin torque transfer
KW - spin-torque nano-oscillators
UR - http://www.scopus.com/inward/record.url?scp=85030162311&partnerID=8YFLogxK
U2 - 10.1088/1361-6463/aa860b
DO - 10.1088/1361-6463/aa860b
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AN - SCOPUS:85030162311
SN - 0022-3727
VL - 50
JO - Journal of Physics D: Applied Physics
JF - Journal of Physics D: Applied Physics
IS - 41
M1 - 415002
ER -