Oscillatory Magnetic Dynamics of a Nanoparticle Driven by an External field and Spin-polarized Current

Authors T.V. Lyutyy , D.M. Krekshyn

Sumy State University, 2, Rimsky Korsakov Str., 40007 Sumy, Ukraine

Е-mail lyutyy@oeph.sumdu.edu.ua
Issue Volume 10, Year 2018, Number 5
Dates Received 22 July 2018; published online 29 October 2018
Citation T.V. Lyutyy, D.M. Krekshyn, J. Nano- Electron. Phys. 10 No 5, 05033 (2018)
DOI https://doi.org/10.21272/jnep.10(5).05033
PACS Number(s) 75.50.Tt, 76.20. + q, 85.75. – d
Keywords Landau-Lifshitz-Gilbert equation, Slonczewski –Berger current terms, Uniform Precession, Linear approximation, Writing MRAM cell.

The magnetic dynamics of a uniform magnetized nanoparticle, under a constant and periodic external fields, as well as a constant and periodic spin-polarized current, is considered. The Landau-Lifshitz-Hilbert equation with a current terms in the form of Slonczewski –Berger are utilized. Three modes of steady-state motion of the nanoparticle magnetic moment are described analytically. In particular, for the precession mode, the algebraic equations with respect to precession angle and lag angle are derived. The solutions of these equations characterize this type of dynamics. For the mode of synchronous oscillations, which is typical for the case of small anisotropy and a periodic external action, the amplitudes dependencies on the system parameters are obtained. Finally, for the mode of small oscillations under the action of an alternating spin-polarized current, expressions for the frequency dependence of the amplitudes of oscillations are found. These dependencies allow to better understand the mechanisms of switching magnetization under the action both of the alternating field and spin-polarized current, and select the optimal parameters for a fast and reliable recording process in media devices.

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English version of article