Browsing by Author "Useinov, Artur"

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Digital readout optimization of the random resistive states in magnetic tunnel junction
(2020-01-01)
Egler, Thomas
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Dittmann, Hans
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Useinov, Artur
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國際半導體學院
;
International College of Semiconductor Technology
True random number generators (TRNGs) provide a wide area of applications and can be fabricated on the basis of magnetic tunnel junctions (MTJs). This work represents the modeling of TRNG readout optimization, where the induced digital random bit is detected within only a single computational period. The period contains two sub-cycles: write and joined read & reset cycles. The system has a valuable potential to become stochastically independent after calibrating at the desired working point against the factors, which cause to the signal deviations: temperature-induced, material degradation or other problems.
Direct Tunneling and Related TMR Anomalies in Magnetic Tunnel Junctions With Embedded Nanoparticles
(2019-12-01)
Turenne, Diego
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Useinov, Artur
;
國際半導體學院
;
International College of Semiconductor Technology
This article shows simulations of the electron direct tunneling through the MgO insulating layer in the magnetic tunnel junction with embedded non-magnetic and magnetic nanoparticles (NPs). The approach of weak magnetic NPs is considered at low temperature, where the related values of the electron wavenumbers, as well as exchange energy in NPs, are a few times smaller than in the bulk. The results show the opportunities for the significant enhancement of the tunnel magnetoresistance (TMR) with voltage. The theory predicts and explains some anomalous periodicity of TMR with voltage including the stable plateau at some conditions.
Spin-resolved electron transport in nanoscale heterojunctions. Theory and applications
(2020-08-15)
Useinov, Artur
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Lin, Hsiu-Hau
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Useinov, Niazbeck
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Tagirov, Lenar
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國際半導體學院
The work represents the extended theoretical model of the electrical conductance in nanoscale magnetic pointlike contacts. The developed approach describes diffusive, quasi-ballistic, ballistic and quantum regimes of the spin-resolved conductance that is important for further development of the contact Andreev reflection spectroscopy, heterojunction models, scanning tunnel microscopy techniques. As a benefit, the model provides a unified description of the contact resistance from Maxwell diffusive through the ballistic to purely quantum transport regimes without residual terms. The model of the point contact assumes that the contact area can be replaced by a complicated object (i.e. the tunnel barrier or complicated one with nanoparticles, narrow domain wall, etc.), where the potential energy profile determines its electrical properties. The model can be easily adapted to particular contact materials, its physical properties and species of the contact area.