Anatolii Grigorovich Belous

Institute of General and Inorganic Chemistry · Solid States Cemistry

Ceramics with nominal chemical composition CaCu3Ti4O12 (CCTO), CaCu3Ti3.96Al0.04O11.96F0.04 (CCTOAF), and Ca0.98Mg0.08Cu2.94Ti3.96Al0.04O11.96F0.04 (CCTOMAF) were prepared by the solid-state reactions technique. Using SEM, EDX, XPS, EPR, NMR, and complex impedance spectroscopy, the microstructure, elements distribution, chemical composition of grai...

LiNi0.6Co0.2Mn0.2O2 (NMC 622) cathode material is widely used for lithium-ion batteries. The effect of the method of creating a protective layer of Li1.3Al0.3Ti1.7(PO4)3 (LATP) on the electrochemical characteristics of commercial cathode material NMC 622 was investigated. It was found that both methods of LATP coating did not affect the crystal str...

Amplification of a dosimetric EPR signal in mineralized biological materials available in limited quantities has been demonstrated in this paper. Powders of irradiated enamel, dentin, and bone tissue were placed into silica ampoules with the outer diameter close to 1.4 mm. To amplify the signal, the dielectric insert in the form of cylinder with th...

La 0.775 Sr 0.225 MnO 3 nanoparticles were synthesized by sol-gel method with heat treatment at T = 1073 K and covered with silica shells of various thicknesses. Analysis of their experimental ferromagnetic resonance spectra was carried out in the temperature range of 77–290 K. The linewidth of absorption curves change in a nonlinear manner in coat...

A method of obtaining a solid polymer electrolyte for lithium-ion batteries based on polyethylene oxide-containing (PEO) supramolecularly organized system segmented polyurethane – segmented oligourethane with LiClO4(PUU-OUU-LiClO4) is proposed. The introduction of LiClO4 into PUU-OUU leads to an extreme increase in the glass transition temperature...

The properties of the synthesized films of organic-inorganic perovskites CH3NH3PbI3 obtained at various ratios of starting reagents (PbI2 and CH3NH3I) have been studied. As a solvent, we used chemically pure dried dimethylformamide (DMF). Organic-inorganic perovskites are promising for photovoltaic applications. It has been shown that regardless of...

Ceramic samples of Na-doped lithium lanthanum titanates have been synthesized by solid-state reaction technique. Scanning electron microscopy has shown that the grain size of ceramics in La0.5Li0.5-xNaxTiO3 solid solutions decreases with an increase in sodium concentration. Complex impedance spectroscopy measurements demonstrate that the origin of...

The influence of DMF and DMSO solvents on the properties of organic–inorganic perovskite films obtained at the ratio of starting reagents PbI2:CH3NH3I = 1:2 was studied. It was found that a dense film is formed from solutions in DMSO. XRD and fluorescence spectroscopy have shown that the use of DMSO promotes the formation of perovskite films that a...

На основi керамiки легованого тетратитанату барiю (BaTi4O9 + 8,5% ZnO) з дiелектричною сталою e = 36 i низькими дiелектричними втратами (tg б ≈ 1,887 · 10−4) у дiапазонi частот 9–10 ГГц розроблено дiелектричнi вставки цилiндричної форми та певних розмiрiв в стандартний металевий ЕПР спектрометр. Встановлено, що їх використання дозволяє пiдсилити си...

We present the results of studies of the photoelectric properties of perovskite CH3NH3PbI2.98Cl0.02 films deposited on a glass substrate using the spin-coating method. The unit cell parameters of perovskite are determined, by using X-ray diff ractometry. It is shown that the fi lm morphology represents a net of non-oriented needle-like structures w...

Analysis of the ferromagnetic resonance (FMR) experimental spectra of CoFe2O4 nanoparticles at T=4.2 K was performed. It allowed to estimate the contribution of magnetoelastic anisotropy to the total anisotropy field of these nanoparticles.

The ceramics СaСu3Тi4–xAlxО12-y-0.5xFy were prepared using solid-state reactions technique and pre-synthesized CaTiO3. It was found that the resistances of both the grain boundary RGB and the interface between sample and electrode RSE increase at the combined introduction of Al³⁺ and F– ions. At 1100 ºС, a decrease in dielectric properties after 12...

The ferromagnetic resonance (FMR) spectra of Fe3O4 and ZnFe2O4 nanoparticles with organic synthesis products were studied at T = 4.2 K. It was determined that the sintering of nanoparticles induced by postsynthesis heat treatment forms a mechanically unstable transition layer between them. Changes in the FMR spectra of Fe3O4 nanoparticles synthesiz...

The latest results in the field of design of and research on organic-inorganic perovskites are summarized. The influence of chemical and physical factors, in particular the ratio of starting reagents, such as solvents, including polymers, temperature, and light radiation, on the formation of perovskite films and the features of their crystal struct...

Organic-inorganic perovskites are unstable materials to external conditions that prevent their widespread use to convert solar energy. Changing the starting reagents ratio and the solvent can affect the structural and electrical properties of perovskites. Films of organic-inorganic perovskites CH3NH3PbI3 at different ratios of starting reagents (Pb...

Magnetic properties of the sets of Fe3O4(core)/CoFe2O4(shell) composite nanoparticles with a core diameter of about 6.3 nm and various shell thicknesses (0, 1.0, and 2.5 nm), as well as the mixtures of Fe3O4 and CoFe2O4 nanoparticles taken in the ratios corresponding to the core/shell material contents in the former case, have been studied. The res...

Two different chemical methods (co-precipitation from solution of diethylene glycol and cryogenic method) for the synthesis and dispersing of magnetic nanoparticles into water with coating by double layer of sodium oleate are compared with respect to the final structural organization of magnetic fluids obtained. Basing on the data of X-ray diffract...

Combined study of magnetization reversal and AC field-induced processes has been carried out for lanthanum-strontium manganite nanoparticles with an average particle size near 30 nm. Hysteretic behavior with magnetic anisotropy fields of the order of one hundred Oersteds is independently confirmed by magnetic and calorimetric measurements. The regu...

Effect of shell thickness on DC magnetic parameters (saturation magnetization, coercivity, blocking temperature) and AC losses (specific loss power, intrinsic loss power) has been studied for Fe 3 O 4 /CoFe 2 O 4 core/shell-like magnetic nanoparticles with a fixed diameter of core ∼6.3 nm and an effective thickness of shell up to 2.5 nm. Regulariti...

Presented in this work are the results of our study of the photoelectric properties of perovskite $CH_3NH_3PbI_{2.98}Cl_{0.02}$ films deposited on a glass substrate using the spin-coating method. The unit cell parameters of the perovskite are determined using x-ray diffractometry. It is shown that the film morphology represents a net of non-oriente...

Nanoparticles of lanthanum-strontium manganite were synthesized via different methods, namely, sol-gel method, precipitation from non-aqueous solution, and precipitation from reversal microemulsions. It was shown that the use of organic compounds and non-aqueous media allowed significantly decreasing of the crystallization temperature of nanopartic...

The effect of starting reagents (PbI2:{CH3NH3I + CH3NH3Cl}) with different ratios in raw solutions on the microstructure of films of organic-inorganic perovskites CH3NH3PbI3-xClx, as well as on the electrical properties, has been investigated. It was found that the crystallinity is increased sharply when the ratio of the starting reagents increases...

Effect of zinc substitution on magnetic properties and AC heating characteristics of Ni1−xZnxFe2O4 (x = 0–1) nanoparticles has been studied. Magnetic parameters, such as saturation magnetization, Curie temperature, specific loss power, have been determined for the samples. It is shown that the samples with a higher zinc concentration (x > 0.5) disp...

The 3D printing compatible technology of “ferrite – nonmagnetic dielectric” composite structures preparation was proposed. Composite resonant elements for applications in the centimeter range of microwave frequencies comprising nonmagnetic dielectric BaTi4O9-ZnO and ferrite film made from spinel nickel-zinc ferrite Ni1−xZnxFe2O4 (x = 0; 0.25; 0.5;...

The Li0.33Lia0.56TiO3 and Li1.3Ti1.7Al0.3(PO4)3 ceramics with the structures of defect-perovskite and NASICON structures with conductivity of 1–6 × 10⁻⁶ S/cm at the room temperature are obtained. Ceramic electrolytes were developed for a solid-state battery EMF of 4.1 V and high discharge stability in time. Discharge characteristics of solid-state...

Weakly agglomerated zirconium dioxide nanopowders stabilized by complex oxides of scandium (III) and cerium (IV) were synthesized by precipitation from aqueous solutions. Using weakly agglomerated nanopowders, thick films were prepared by tape casting on a-Al2O3 substrates. These thick films have high oxygen conductivity; and their electron conduct...

Structural aspects of powders containing magnetic nanoparticles Fe3O4/CoFe2O4 with the anticipated “core-shell” structure are considered by means of comparative analysis with individual particles of Fe3O4, CoFe2O4 in accordance of data obtained from X-ray powder diffraction and small-angle scattering of X-ray (synchrotron) radiation and neutrons. I...

Approaches have been developed for the creation of magnetic core/shell nanocomposites derived from (La,Sr)MnO3 and SiO2 with particle diameter 40-45 nm. SQUID magnetometry has shown that the presence of the SiO2 shell on the surface of the manganite nanoparticles results in lower saturation magnetization values at the constant blocking temperature....

The microstructure, crystal chemical parameters and electrical–physical properties of samples of barium titanate-based dielectric and semiconductor ceramics were investigated in a wide frequency range. The contributions of different nanointerfaces to the permittivity of samples under investigation have been determined.

The work highlights peculiar features of synthesis and summarizes important properties of nanoparticles and films based on two types of oxide magnets: with spinel and perovskite-type structures. The attention is drawn to the differences in the processes underlying the formation of crystalline phase in the materials of each group. It is shown that f...

Magnetostatic properties and AC magnetic heating characteristics of (La,Sr)MnO3 nanoparticles with substitutions in manganese and lanthanum sublattices have been studied. The nanoparticles with average sizes in the range 25-38 nm were synthesized via sol-gel method. Fe substitution for Mn, as well as Sm substitution for La have been used in the exp...

Two sets of core/shell magnetic nanoparticles, CoFe2O4/Fe3O4 and Fe3O4/CoFe2O4, with a fixed diameter of the core (~ 4.1 and ~ 6.3 nm for the former and latter sets, respectively) and thickness of shells up to 2.5 nm were synthesized from metal chlorides in a diethylene glycol solution. The nanoparticles were characterized by X-ray diffraction, tra...

The influence of the synthesis conditions (rotation speed used for spin-coating deposition of the film, film drying temperature, and the ratio of the PbI2 and CH3NH3I reactants in solutions) on the micro-structure, phase composition, and spectral-luminescent properties of films of organic-inorganic perovskite CH3NH3PbI3–xClx (x = 0, 0.02) was eluci...

Two sets of Nd-doped La0.7Sr0.3MnO3 nanoparticles were synthesized via sol-gel method with further heat treatment at 1073 and 1573 K, respectively. Crystallographic and magnetic properties of obtained nanoparticles were studied, and the effect of synthesis conditions on these properties was investigated. According to X-ray data, all particles cryst...

In this work, the influence of different thermal sintering treatments on Li1.3Al0.3Ti1.7(PO4)3 NASICON thick films has been investigated. The isostatic lamination step performed before the thermal sintering of thick films has demonstrated to improve film density and grain size, increasing "bulk" and grain boundary Li-conductivities. The confocal Ra...

Magnetic nanoparticles constitute promising tools for addressing medical and health-related issues based on the possibility to obtain various kinds of responses triggered by safe remote stimuli. However, such richness can be detrimental if different performances are not adequately differentiated and controlled. The aim of this work is to understand...

In this work, the effect of starting reagents (CH3NH3I:PbI2) with different ratios in raw solutions on the microstructure, phase composition, absorption, and luminescence spectra of the films of organic-inorganic perovskites CH3NH3PbI3 has been investigated.

Ferroelectrics with very large (“colossal”) magnitudes of permittivity (e > 1000) are demanded for modern applications: capacitance-based energy-storage and microwave devices, memory elements, etc [1]. Colossal values of the permittivity (CMP) can arise due to different phenomena, including ferroelectricity, charge-density waves, metal-dielectric i...

The present work is devoted to a deeper understanding of the nature of colossal permittivity of BaTiO3-based ceramics with the view of its further enhancement.

Our work shows the effect of starting reagents (CH3NH3I:PbI2) with different ratios in raw solutions on the microstructure, phase composition, absorption, and luminescence spectra of the films of organic-inorganic perovskites CH3NH3PbI3.

Barium-strontium titanate (BST) Ba0.6Sr 0.4 TiO3 and lanthanum-lithium titanate (LLT) La0.5Li0.5TiO3 nanopowders and thin films have been obtained via the modified Pechini route. Polyesterification and complexation processes of gel formation have been examined. Hypothetical models of coordinative polymers formed in sol-gel system have been suggeste...

A perovskite phase with the composition Li0.33La0.57TiO3 modified with up to 7 wt % Bi2O3, SiO2, Li3PO4, or Li3BO3 has been prepared by solid-state reactions. The samples in the LLTO–Li3PO4, LLTO–Bi2O3, and LLTO–SiO2 systems were single-phase over the entire composition range studied. In the LLTO–Li3BO3 system, increasing the lithium borate concent...

Pure perovskite structure Li0.5 − yNayLa0.5Nb2O6 compounds with y values of 0, 0.1, 0.2, 0.3, 0.4, 0.43, 0.48 and 0.5 have been synthesized. Ceramics of these compounds were studied by X-ray diffraction and impedance spectroscopy in the frequency range of 10 Hz to 10 GHz and temperature interval from 300 K to 800 K. The linear increase of the latti...

Ln-doped La0.7−xLnxSr0.3MnO3 (Ln – Nd and Sm) nanoparticles were synthesized via sol-gel method with further heat treatment at 800 °C. Crystallographic, magnetic and calorimetric properties of the obtained nanoparticles have been studied. According to X-ray data, all particles have crystalline perovskite structure and lattice cell volume decreases...

In the last decade, ferromagnetic nanoparticles that are able to be heated under an AMF (alternating magnetic field) have gained considerable interest in the field of nanotechnology. The current study explores the peculiarity of the synthesis and the properties of Fe3O4 and (La, Sr)MnO3 nanoparticles by cryochemical and sol-gel technology, as well...

Structure characterization of magnetic fluids (MFs) synthesized by three different methods in aqueous solutions of agarose was done by means of small-angle neutron (SANS) and synchrotron X-ray scattering (SAXS). The differences in the complex aggregation observed in the studied magnetic fluids were related to different stabilizing procedures of the...

La1-xSrxMnO3 nanoparticles were synthesized by precipitation from diethylene glycol solution. Features of synthesis were studied using 1Н, 13С, 139La nuclear magnetic resonance (NMR) investigations. The obtained results showed that the complexation reaction between diethylene glycol and metal cations takes place during the synthesis. These complexe...

Crystallographic, magnetic, and magnetoresistive properties of heterosubstituted lanthanum-strontium manganite ceramic samples doped with Fe are studied. The samples for investigation are fabricated by sintering of powders synthesized by sol-gel method. As shown, the lattice unit-cell volume decreases with the growing of Fe content that points on p...

La 1x Sr x MnO 3 (х  0,15—0,60), виготовлених золь—ґель-методою. Кристалографічні параметри визначалися за допомогою рентґенівської дифракції. Вимірювання електричних властивостей виконувалися в тем-пературному інтервалі 77—380 К як у магнетному полі, так і без нього. Проаналізовано температурні залежності електричних та магнеторезис-тивних власт...

Two series of nanosized particles of CoFe2O4 spinel ferrites were synthesized from metal salts with the use of high-energy ball milling with addition of NaCl as a growth agent (CFO-NaCl series) or without it (CFO series). The particles were characterized by atomic force microscopy, magnetic and calorimetric measurements. It is shown that the averag...

Two series of nanosized cobalt spinel ferrites CoFe2O4 are synthesized from metal salts using high-energy ball milling with the addition of NaCl as a growth agent (series CFO-NaCl), and without (CFO Series). The particle properties are characterized using atomic force microscopy, as well as magnetic and calorimetric measurements. It is shown that t...

Results of simulation of the electron spin resonance absorption peak shape for the magnetic nanopowder are presented. The influence of the magnetic particle diameter on the shape and on the width of the resonance peak is shown. Simulation results show a good agreement with the experimental data of the electron spin resonance absorption in the Fe 3...

(1−x)BaTiO3–xM0.5Bi0.5TiO3 (M = Li, Na, K) solid solutions were prepared using BaTiO3 pre-synthesized by oxalate method. The stability limits of (1−x)BaTiO3–xLi0.5Bi0.5TiO3 solid solutions have been established. It was shown that increase in M0.5Bi0.5TiO3 concentration results in reduction of ceramic grain size in the (1−x)BaTiO3−xM0.5Bi0.5TiO3 (M...

Codoping with iron, cerium, and copper oxides has been proposed as a means of improving the performance of scandium-containing zirconia-based solid electrolytes. We have examined three procedures for the synthesis of the (ZrO2)0.825(CeO2)0.07(Sc2O3)0.07(Fe2O3)0.035 solid solution through precipitation from solution. It has been shown that the highe...

Fe-doped La0.77Sr0.23Mn1 - y Fe y O3 nanoparticles have been synthesized by sol-gel method, and ceramic samples based on them were sintered at 1613 K. Crystallographic and magnetic properties of obtained nanoparticles and ceramic samples have been studied. It has been established that cell volume for nanoparticles increases with growing of iron con...

Structure of magnetic fluids, which were produced by two methods of synthesis and stabilization of magnetite nanoparticles in aqueous solution of agarose, was considered in the given work. Complex aggregation in the colloidal systems was found according to small-angle synchrotron X-ray scattering (SAXS) technique. Effective size of single polydispe...

In this work, thick films of Perovskite La0.57Li0.33TiO3 (LLTO) and Li-NASICON Li1.3Al0.3Ti1.7(PO4)3 (LATP) Li-conductors have been prepared by tape casting and their microstructure and homogeneity assessed by SEM and confocal Raman spectroscopy. Electrical properties of thick films have been investigated by Impedance spectroscopy. In particular, b...

The La0.56Li0.33TiO3 ceramic with the structure of defect perovskite and high conductivity of (2-4) x 10(-3) S cm(-1) at the room temperature is obtained. Ceramic electrolyte based on La0.56Li0.33TiO3 is developed for a lithium-air cell with EMF of 3.1 V and high discharge stability in time. Discharge characteristics of a lithium-air cell are studi...

Lio.5-xNaxLao.5Nb206 compounds crystallize into perovskite structure. Lithium ions are mobile in this system and the aim of partial Li+ -> Na+ substitution is to investigate lithium conduction mechanism in such perovskites. The single phase compounds with x changing from 0.1 to 0.5 were synthesized and dense ceramic samples of the compounds were si...

An investigation of the composite “α-Al2O3 dielectric resonator-thick ferrite film” heterostructures magnetic field tunable microwave properties has been conducted. Thick high-density high-quality NiFe2O4 spinel and M-type hexaferrite BaFe12O19 films were deposited on the surface of the dielectric by tape-casting technique. Specific organic suspens...

Dielectric resonator aided sensitivity-enhancing electron paramagnetic resonance was successfully applied to small single crystals of the previously reported metal–organic framework compound ∞3[Cu2ICu2II(H2O)2L2Cl2] in a conventional X-band EPR spectrometer at 7 K sample temperature to reveal the nature of mononuclear Cu2+ ion defect species. We fo...

Abstract We have shown the possibility to obtain M-type barium hexaferrite thin films with thickness of ~200–450 nm on the surface of dielectric α-Al2O3 substrates with low microwave dielectric loss (tan δ ~ 10−4 GHz) by a sol–gel method. For the production of high-dense homogeneous thin films of M-type barium hexaferrite (BaFe12O19, BHF) with nano...

Nanocrystalline and weakly agglomerated particles of ferromagnetic compounds La1-xSrxMnO3 with the perovskite structure have been synthesized by sol-gel technique followed by different types of mechano-chemical processing. The effect of mechano-chemical processing on the particle size has been defined from microstructural studies. Synthesized nanop...

The ability to controllably tune the heating efficiency of magnetic nanoparticles in an AC magnetic field is highly desirable for their application as mediators of magnetic hyperthermia. Traditional approaches to understand and govern the behavior of hyperthermia mediators include a combination of quasistatic and high-frequency (~100 kHz) magnetic...

Conditions for the formation of (1- x )BaTiO 3 – x Li 0.5 Bi 0.5 TiO 3 (0 ≤ x ≤0.6) solid solutions with positive temperature coefficient of resistance (PTCR) effect were studied. Solid solutions were prepared by solid state reaction technique. Samples were sintered under reducing atmosphere N 2 /H 2 in the temperature range 1200–1450 °C with subse...

Three types of ferromagnetic nanostructures based on barium hexaferrite (BaFe12O19), lanthanum-strontium manganites with perovskite structure ((La,Sr)MnO3) and materials with spinel structure (AFe2O4, A = Ni, Zn, Co, Mn, Fe) have been synthesized by precipitation from aqueous and nonaqueous solutions, by the sol-gel method and from microemulsions....

In this work, iron oxide nanoparticles have been synthesized by precipitation in diethylene glycol, by cryochemical synthesis, in microemulsions using surfactants Triton X-100, Brij-35 and CTAB. Comparative spectroscopic, thermal, X-ray diffraction, ⁵⁷ Fe zero-field Mössbauer and magnetic studies of the synthesized nanoparticles have been carried o...

Structural and magnetic characteristics of (La,Sr)MnO3 nanoparticles synthesized by different methods have been studied in the work. The specific loss power which is released on the exposure of an ensemble of synthesized particles to alternating magnetic field was calculated and measured experimentally. The contributions to the specific loss power...