arXiv subjects

Artur Useinov

Publications and source records attributed to Artur Useinov.

5 recordsLinked to original sources

arXiv2026

Magnetoresistance ratio of a point-like contact with a 1 nm wide domain wall at different MFP asymmetries

This work presents a unified theoretical framework for spin-resolved electron transport in magnetic point contacts (PCs) in nanoscale dimensions. This work advances existing research by presenting a model which seamlessly transitions between Sharvin ballistic and Maxwell-Holm diffusive limits across the wide range of relevant contact sizes without incorporating empirical fitting factors. We analyzed the magnetoresistance (MR) of magnetic PCs formed with two ferromagnetic monodomains that may have parallel and antiparallel magnetization alignment, forming a constrained domain wall approximately 1.0 nm wide. The calculated MR exhibits strong dependence on scaling parameter (normalized contact radius), ratios of spin-dependent mean free paths, and Fermi wave-vectors. Furthermore, the calculated MR exhibits physically meaningful behavior over a wide range of spin-asymmetry parameters. In most regimes, the MR decreases with increasing normalized point-contact radius, becoming negative at some conditions. These results demonstrate that nanoscaled magnetic PCs have great efficiency in terms of magnetoresistnace change and promising for application due to their simplicity.

cond-mat.mes-hall↗

arXiv2025

A Novel Methodology of Visualizing Orthorhombic Phase Uniformity in Ferroelectric Hf0.5Zr0.5O2 Devices Using Piezoresponse Force Microscopy

Ferroelectric Hf0.5Zr0.5O2 (HZO) thin films are promising for next-generation memory and logic devices due to their CMOS compatibility and scalability. The spatial uniformity of the orthorhombic (O) phase is crucial for optimizing ferroelectric properties like remnant polarization. This work introduces a novel piezoresponse force microscopy (PFM) approach for 2D mapping of O-phase uniformity in HZO films (5 nm, 9 nm, and 20 nm), further quantifing O-phase distribution by distinguishing polarized O-phase regions from non-polarized tetragonal/monoclinic (T/M) phases. Our results reveal that the 9 nm film exhibits the most uniform O-phase and highest remnant polarization. This PFM-based method enables comprehensive phase characterization without requiring complicated facilities, broadening access to phase analysis and advancing ferroelectric thin-film research for memory and logic applications.

cond-mat.mtrl-sci↗

arXiv2022

3T-1R Analog Write and Digital Read of MRAM for RNG and Low Power Memory Application

This work represents integration of MTJ with 30nm FinFET for low voltage analog write operations and readout optimization for the p-bit or true random number generator (TRNG), where the induced p-bit, the probabilistic state of the magnetic tunnel junction (MTJ), is detected within only a single computational period. The period contains two sub-cycles: write and joined read & reset cycles. The operation with MTJ becomes stochastic, independent after calibrating at the desired working point against the factors, which can induce the signal deviations, e.g. temperature, material degradation or external magnetic field.

cs.ET↗

arXiv2022

Application of the point-like contact model: Resistance Oscillations of the Domain Wall in Magnetic Nanowires and Junctions due to Mean Free Path Effects

This work is focused on determining the electrical resistance, which induced by single domain wall in magnetic nanowire with a negligible defect. The provided model covers a wide range of nanowire's diameters. The obtained result demonstrates a few orders rapid reduction of the domain wall resistance accompanied by its possible deviations versus the diameter growth ranging from 1.2 nm to 15.2 nm. The origin of these deviations, which are also identified as oscillations, is referred to the non-uniform electron scattering on the domain wall due to the intermixing electron scattering conditions: ballistic for one spin channel and quasi-ballistic for other one with opposite spin direction. It may happen when the domain wall width by value is approximately in between two lengths: a mean free path with the spin down and spin up. The indirect evidence of this finding is also coming from the fact that homogeneous nanowires shows the most valuable domain wall resistance oscillations by magnitude rather than segmented magnetic nanowires. In addition to the approach, where DW width is constant, the other reasonable model is used when the domain wall can be constrained for some conditions. The same results are valid for magnetic junctions with domain wall. Finally, resistance simulation in the diffusive range, when a diameter of the nanowire (or point-like junction) is larger than any of spin resolved mean free path of electrons, successfully follows experimental data for the single and double domain wall resistances available in literature.

cond-mat.other↗

arXiv2017

Quantum point contact: a case of spin-resolved electron transport

The work presents the extended theoretical model of the electrical conductance in non-magnetic and magnetic nano-size point contacts. The developed approach describes diffusive, quasi-ballistic, ballistic and quantum regimes of the spin-resolved conductance. It is based on the electron transport through metallic junction within approach of the circular constriction. The model provides unified description of the contact resistance from Maxwell diffusive through the ballistic to purely quantum transport regimes without any residual terms depending from the scale. An application are given for experimental treatment of the golden nanocontacts as a non-magnetic case and Permalloy nanowire with/without domain wall as example for the magnetic system. The model of quantum point contact assumes that contact area can be replaced by the quantum object (i.e. magnetic tunnel junction, narrow domain wall, etc.), where potential energy profile determine its electrical properties.

cond-mat.mes-hall↗