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Registration Number

0220U100245, 0119U101609 , R & D reports

Title

Elements of ultrafast neuron systems on the basis of antiferromagnetic spintronic nanostructures.

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Head

Tovstolitkin Aleksandr I.,

Registration Date

14-01-2020

Organization

Department for special training National academy of science of Ukraine at Kiev University

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The physical mechanisms of signal generation of the sub-THz and THz frequency bands in the spin Hall oscillator (SHO) based on AFM were analyzed, and the electrodynamic characteristics of such systems are calculated. Using the methods of numerical modeling, the process of generation of pulse signals in the AFM SHO which is controlled by weak input AC and DC bias current is investigated. It is shown that SHO based on a bianisotropic AFM can act as a generator of δ-pulse with duration of ~ 4 ps. The conditions of existence of different operation modes of such generator, when the output δ-pulse is not generated under the action of the input signal, and one or more output δ-pulses are generated are established. A theory of magnetization dynamics in ferrimagnetic materials with antiparallel aligned spin sublattices under the action of spin-transfer torques (STTs) is developed. In contrast with antiferromagnets, the magnetic sublattices in ferrimagnets are formed by different magnetic ions, which results in a symmetry breaking in the dynamic equations for Néel’s vector. We demonstrate that this symmetry breaking becomes crucially essential for the THz signal extraction in ferrimagnetic spin-torque oscillators. As an example, we consider magnetization dynamics in GdFeCo layers in spin Hall and nanocontact spin-torque oscillator geometries. We demonstrate that (i) the application of spin current leads to a conical precession of Néel’s vector with sub-THz frequencies, (ii) in the spin Hall geometry, the conical precession leads to sub-THz oscillations of the Hall voltage, and (iii) in the nanocontact geometry the Néel’s vector precession leads to sub-THz oscillations of the magnetoresistance.  

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Ivanov Borys O.
Artemchuk Petro Yu.
Krаvets Anаtolii F.
Lytvynenko Yaryna M.
Moiseienko Vladyslav A.
Prokopenko Ludmyla E.
Prokopenko Oleksandr V.
Romaniuk Olena V.
Slobodianiuk Denys V.
Sulymenko Olga R.

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2020-04-02