arXiv subjects

Taisiia O. Kuzmenko

Publications and source records attributed to Taisiia O. Kuzmenko.

3 recordsLinked to original sources

arXiv2026

Impact of Carbon Contamination on the Low-Temperature Electric Conduction of the Spark-Plasma Sintered Barium Titanate Ceramics

The dielectric and electric conduction properties of BaTiO3 samples fabricated by the spark plasma sintering with additional contamination by different content of carbon have been investigated in the temperature range from 77 through 408 K in small non-heating electric fields and in the range of 77 - 200K under strong electric fields up to 20 kV/cm. The effective dielectric permittivity of the samples with additional carbon achieves colossal values at low frequency, up to several units per 106 at 393 K. In the low temperature range, it remains very high magnitude, 10^4 -10^5 at low frequency and is strongly dependent on the carbon content. The electric conduction in the range of 77 - 200 K bears the hopping conduction and obeys the Mott law. We also studied electric conduction and effective dielectric permittivity vs electric field strength in the range of 77 - 200 K. The results are explained within the frames of hopping conduction theory and suggestion on different constituents in polarization processes and electric conduction.

cond-mat.mtrl-sci↗

arXiv2026

Electric Charge Transport and Dielectric Properties of the Barium Titanate Ceramics Obtained by Spark-Plasma Sintering with Different Carbon Content

Barium titanate (BaTiO3) ceramics with a different content of carbon were synthesized by spark-plasma sintering (SPS) at the temperature of 1100 C in vacuum under pressure. The concentration and distribution of carbon impurity inside the samples is estimated by scanning electron microscopy (SEM). The resistivity vs temperature and electric field dependences of the SPS ceramics with different carbon concentration have been studied. It is shown that their conduction is determined by the variable range hopping mechanism and obeys the Mott law. The density of localized states and localization radius of the electron wave function are determined. The difference in low-temperature resistivity of the SPS ceramics is caused by carbon concentration and connected with it variation of the dielectric permittivity. The relative dielectric permittivity of the SPS ceramics is colossal and reaches the values of 10^5 - 10^6 order. The larger carbon concentration is, the smaller the permittivity and resistivity are within the Mott hopping conduction temperature range. In the range from 250 K to 408 K one observes that the dielectric permittivity strongly increases forming a maximum in all samples, which may be related to the phase transition. Along with this, resistivity manifests a simultaneous sharp decrease. The decrease of resistivity along with the characteristic dependence of resistivity vs dielectric permittivity in the Mott conduction temperature range, evidences the validity of Heywang model for the description of SPS ceramics conduction mechanisms. The resistivity strongly decreases with increasing frequency in the AC regime, which agrees both with models of hopping conduction and effects based on the Maxwell-Wagner model. The studied SPS BaTiO3 ceramics are attractive for applications in energy storage and sensorics.

cond-mat.mtrl-sci↗

arXiv2025

Dispersed multi-walled carbon nanotubes in polyvinyl butyral matrix for transparent ionic conductive films

In this work, we develop methods for increasing the dispersion degree of agglomerated multiwalled carbon nanotubes with subsequent introduction of them into polyvinyl butyral to create transparent conductive films. The influence of proton and a-proton solvents in combination with potassium triiodide (KI3) as a redox component for oxidation of the multiwalled carbon nanotubes surface, which reduces agglomeration due to electrostatic repulsion, is investigated. It is demonstrated that a-proton solvent cyclohexanone ensures a smaller size of the agglomerates (30-300 nm, with a maximum of ~145 nm) compared to proton solvent propyl alcohol (100-3000 nm, with a maximum of ~920 nm). The reduced aggregation is associated with the formation of oxygen-containing functional groups (C=O, C-O, C-O-C, and COO), which increase electrostatic stabilization. The impedance analysis showed that the constant component of the conductivity in the samples with multiwalled carbon nanotubes and a-proton solvent shifts to frequencies of ~104 rad/s after the addition of the redox component, which indicates the formation of ion-conducting channels and stabilization of the jump charge transfer.

cond-mat.mtrl-sci↗