Nanoscale physics

Electrical excitation of magnetic waves in nanoheterostructures 
Korostil A.A.1 
1Department of Physics of Meso- and Nanocrystalline Magnetic Structures, Institute of Magnetism NAS and MES  of Ukraine.  Vernadsky av., 36b, Kyiv, Ukraine. E-mail: amand@rambler.ru

Spintronic effect of electric-controlled local spin dynamics under the spin current-induced torque in magnetic nanostructures is the basis for the controlled excitation of the coherent spin waves of given amplitude and phase. The electrically insulating magnetic materials provide their exceptionally low magnetic damping and relative large distances of propagation. The coherent ratio, frequency and possibility of the electrical manipulation of the spin waves are depend  on  the origin of the spin polarization and spin torque exerting on the localized spin that results in the spin wave propagation. The electric-induced spin torque can be exhibited as the spin transfer torque related to conversation of electric current into spin polarized current [1], the spin-orbit torque related to the spin Hall effect of electric current conversation into spin current and spin-orbit torque related to the electric field-induced surface spin polarization in the effective Rashba field [2]. The latter results in the voltage controlled magnetic anisotropy (VCMA) which is characterized as an efficient mechanism for low-energy excitation and propagation of coherent spin waves with given amplitude and phase [3]. In the case of antiferromagnetic nanostructures, VCMA-induced spin waves possess low susceptibility, lack of stray fields, and THz dynamics. The proposed self-consist description of the electric controlled excitation and propagation of spin waves is based on first-principle density functional theory in a tight-binding model realized with second quantization accounting for features of electron and magnetic structures and interface exchange interactions.      

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