Excitation of propagating spin waves in ferromagnetic nanowires by microwave voltage-controlled magnetic anisotropy.
The voltage-controlled magnetic anisotropy (VCMA) effect, which manifests itself as variation of anisotropy of a thin layer of a conductive ferromagnet on a dielectric substrate under the influence of an external electric voltage, can be used for the development of novel information storage and signal processing devices with low power consumption. Here it is demonstrated by micromagnetic simulations that the application of a microwave voltage to a nanosized VCMA gate in an ultrathin ferromagnetic nanowire results in the parametric excitation of a propagating spin wave, which could serve as a carrier of information. The frequency of the excited spin wave is twice smaller than the frequency of the applied voltage while its amplitude is limited by 2 mechanisms: (i) the so-called "phase mechanism" described by the Zakharov-L'vov-Starobinets "S-theory" and (ii) the saturation mechanism associated with the nonlinear frequency shift of the excited spin wave. The developed extension of the "S-theory", which takes into account the second limitation mechanism, allowed us to estimate theoretically the efficiency of the parametric excitation of spin waves by the VCMA effect.
Institute of Magnetism, National Academy of Sciences of Ukraine, Kyiv 03142, Ukraine.
Roman
R
Verba
Department of Electrical and Information Engineering, Politecnico of Bari, I-70125 Bari, Italy.
Mario
M
Carpentieri
Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, I-98166 Messina, Italy.
Giovanni
G
Finocchio
Department of Physics, Oakland University, Rochester, MI 48309, USA.
Vasil
V
Tiberkevich
Department of Physics, Oakland University, Rochester, MI 48309, USA.
Andrei
A
Slavin