This study presents a comprehensive investigation of the CoFe2O4–Pb2ScNbO6 (0.5CFO–0.5PSN) composite, synthesized via a solid-state reaction method. The composite, comprising a ferrite spinel and a relaxor ferroelectric, was characterized using a suite of techniques including dielectric spectroscopy, optical analysis, X-ray diffractometry, magnetometry, magnetodielectric measurements and electrocatalytic testing. At room temperature, the real part of the complex permittivity (ε′) attains a value of 105. Within the temperature range of 100–250 °C, ε′ increases significantly to approximately 1.4 × 106. The temperature dependence of permittivity, ε′(T), exhibits a relaxor behaviour, which is attributed to the diffuse phase transition inherent to the PSN component and contributions from Maxwell–Wagner interfacial polarization. A distinct anomaly in the ε′(T) curve is observed near 450 °C, manifested as a kink followed by a sharp increase. This feature is associated with the transition of the CFO component from a ferrimagnetic to a paramagnetic state. The analysis of the magnetoresistance coefficient, MR(H), reveals that the composite exhibits colossal magnetoresistance (CMR) on the order of 530

M-type barium hexaferrite (BaFe12O19) was synthesized via a self-sustaining solution combustion method followed by short-time calcination at 1000 degrees C. The obtained material exhibits a single-phase magnetoplumbite-type structure (P63/mmc) with a high degree of crystallinity and an average crystallite size of approximately 58 nm. SEM and EDX analyses confirmed a porous morphology and a stoichiometric Ba:Fe:O composition without detectable impurity phases. Raman spectroscopy and XPS investigations confirmed Fe3+ to be the dominant oxidation state, while surface-sensitive measurements indicate the presence of defect-modified oxygen-containing surface states that may contribute to localized electronic states within the band gap. Optical measurements revealed a direct band gap of 2.02 eV and an Urbach energy of 0.16 eV, indicating a moderate degree of structural disorder. Magnetic characterization showed a ferrimagnetic response with a high coercivity (Hc ti 3755 Oe) and a large magnetocrystalline anisotropy (Keff ti 2.9 x 106 erg/cm3), consistent with Mossbauer spectra that resolve five distinct Fe3+ sublattices (12k, 4f1, 4f2, 2a, 2b). The dielectric spectra exhibited a frequency-and temperature-dependent dispersion typical of ferrites, governed by Maxwell-Wagner interfacial polarization and hopping conduction between Fe2+/Fe3+ sites. The ac conductivity followed Jonscher's power law and was dominated by a correlated barrier hopping (CBH) mechanism. The BaFe12O19 catalyst demonstrated pronounced activity in photocatalytic, sonocatalytic, and in particular sonophotocatalytic degradation of methylene blue (MB), reaching ti 92% decolorization within 60 min with an apparent rate constant of 0.0397 min-1. The enhanced performance under combined light and ultrasonic irradiation originates from the interplay of photoexcitation, magnetostrictive and piezoelectric-like responses, and cavitation-induced charge modulation. Local band bending under acoustic deformation enables the participation of electrons in O2 reduction despite the nominally weakly reducing conduction band (ECB ti +0.20 eV), while defect-modified surface electronic states mediate efficient interfacial charge transfer. These findings reveal a synergistic activation mechanism in which hole-driven oxidation and electron-assisted radical generation coexist, highlighting BaFe12O19 as a multifunctional magneto-piezo-photocatalyst with stable dielectric and magnetic properties suitable for advanced environmental applications.

The development of environmentally stable fingerprint powders with excellent adhesion, chemical durability, and high-resolution visualization capability remains an important challenge in forensic science. In the present work, nanostructured spinel CoCr2O4 ceramics were synthesized by a rapid solution combustion method using a mixed urea–glucose fuel system and evaluated as advanced latent fingerprint visualization powders. X-ray diffraction confirmed the formation of a single-phase cubic spinel structure (JCPDS No. 22-1084) with an average crystallite size of approximately 28.6 nm and a lattice parameter of 8.33 Å. XRF elemental mapping, point analysis, and TEM investigations demonstrated homogeneous Co and Cr distribution, negligible residual chlorine, and porous agglomerates composed of nanosized primary particles. FTIR spectra recorded before and after immersion in deionized water and 1 M NaOH for 2 h confirmed the preservation of the characteristic Co–O and Cr–O vibrations, indicating excellent structural stability with only minor surface hydroxylation. Time-dependent UV–Vis measurements revealed that the decrease in absorbance in water originated primarily from physical sedimentation of agglomerated particles, whereas the spectral evolution in alkaline medium reflected particle–electrolyte interactions involving surface hydroxylation and ζ-potential modification. The optical band gap remained nearly unchanged, varying only from 1.80 to 1.90 eV in water and 1.82 to 1.88 eV in 1 M NaOH, demonstrating remarkable electronic stability. Electrochemical impedance spectroscopy exhibited a small charge-transfer resistance and stable Nyquist response over applied potentials of 50–100 mV, confirming efficient interfacial charge transport and excellent electrochemical stability in alkaline electrolyte. Owing to their porous nanostructure, high crystallinity, chemical robustness, and strong affinity toward fingerprint residues, the synthesized CoCr2O4 nanoparticles successfully developed high-contrast latent fingerprints on porous, semi-porous, and non-porous substrates, clearly revealing Level 1, Level 2, and Level 3 fingerprint characteristics. The developed fingerprints retained excellent contrast after ageing up to 80 days, UV irradiation for 60 min, and thermal treatment up to 160 °C, demonstrating outstanding environmental durability. The combination of structural stability, electrochemical robustness, and superior fingerprint visualization establishes combustion-derived CoCr2O4 nanoceramics as promising, cost-effective forensic powders for practical latent fingerprint development under harsh environmental conditions.

Multifunctional polymer-ferrite composites based on poly(vinylidene fluoride) (PVDF) and magnetic fillers are of increasing interest for applications requiring coupled electrical, dielectric, and magnetic responses. However, the relationship between magnetic filler concentration, PVDF phase composition, and the resulting multifunctional properties remains insufficiently understood. In this work, PVDF/BaFe12O19 (PVDF/BaF) composite membranes containing 2-20 wt.% BaF were fabricated using a combined non-solvent and thermally induced phase-inversion (NIPS-TIPS) method. Structural evolution was analyzed by X-ray diffraction and quantitative FTIR spectroscopy, thermal behavior by differential scanning calorimetry, optical properties by diffuse reflectance spectroscopy, dielectric response in the frequency range 10(3)-10(6) Hz, and magnetic characteristics by vibrating sample magnetometry. At moderate filler concentrations (2-10 wt.%), BaFe12O19 nanoparticles acted as effective beta-phase nucleating centers, leading to electroactive phase fractions of 97.7-99.9% and a maximum beta-phase content of 86.7% for PVDF/BaF10. At higher loadings (15-20 wt.%), particle agglomeration and restricted chain mobility promoted a transition toward alpha-phase-dominated crystallization. Thermal analysis indicated competing nucleation and confined crystallization processes, while optical and dielectric measurements revealed nonmonotonic changes associated with interfacial interactions and Maxwell-Wagner-Sillars polarization. Magnetic measurements showed a linear increase in saturation magnetization with filler concentration and a nonmonotonic coercivity dependence with a pronounced change near the critical agglomeration concentration. These results demonstrate that the multifunctional response of PVDF/BaFe12O19 membranes is governed by the interplay between beta-phase nucleation, interfacial polarization, and magnetic particle interactions, with approximately 10 wt.% ferrite providing the most balanced electrical, dielectric, and magnetic characteristics.

In this study, the composition-dependent structural, electrical, optical, and magnetic properties of (1-x) SrFe12O19-xBaTiO3 composites (0.0 <= x <= 1.0) were prepared by solid sate reaction method. The Structural analysis revealed that the unit cell parameters of the SrFe12O19 phase increased with BaTiO3 content, while the lattice constants (a, c) of BaTiO3 exhibited maxima at x = 0.3 and 0.5, accompanied by significant lattice deformation. Optical measurements showed a nonlinear widening of the band gap (Eg), attributed to band discontinuities at heterointerfaces. Magnetic parameters-including saturation magnetization (Ms), remanent magnetization (Mr), and coercivity (Hc)-exhibited both monotonic and non-monotonic variations with x. A consistent decrease in Ms and Mr was observed due to dilution of the magnetic phase, A consistently high squareness ratio (Mr/Ms approximate to 0.42-0.5) across all compositions reflects stable uniaxial anisotropy and comparable domain reversal behavior, supporting the composite's magnetic reliability. Temperature-dependent impedance spectroscopy revealed anomalous dielectric relaxation behavior, particularly at x = 0.3 and x = 0.9, where grain capacitance (Cg) decreased due to reductions in unit cell volume and coherent scattering domain size (D). Notably, the composition x = 0.5 exhibited the highest exchange interaction energy (A) and moderate coercivity, identifying it as a promising candidate for magnetoelectric memory applications. Meanwhile, x = 0.3 displayed pronounced dielectric relaxation and lattice distortion, suggesting its suitability for high-frequency capacitive and strain-sensitive sensor devices.

The Co1-xCdxCr2O4 (x = 0-0.15) magnetic nanoparticles were synthesized by a simple solution combustion method using glucose and urea as fuel. When Cd2+ ions are introduced into CoCr2O4, the phase structure of CoCr2O4 is not changed, but the lattice parameter first increases and then decreases with the increasing of Cd ion concentration, and the crystallite size decreases with the increasing of Cd ion concentration. Because a large number of Cd ions may change the energy state of the grain boundary, promote the abnormal growth of the grain, and thus lead to the increase of the crystallite size, the abnormal phenomenon occurs when the doping amount reaches x = 0.12. The microstructure characterization confirms that the particle size of Co1-xCdxCr2O4 decreased with the increasing of Cd ion concentration, and the agglomeration between the particles was obvious. Magnetic characterization indicates that the magnetic transition temperature, residual magnetization, and squareness ratio of Co1-xCdxCr2O4 (x = 0.03) are larger than those of other samples. After the Cd ion concentration is increased further, the anti-ferromagnetic coupling is enhanced due to ion doping, which leads to a decrease in the average particle size and lattice parameter of Co1-xCdxCr2O4, a decrease in the number of magnetic domains and domain walls contained in each particle, and a corresponding decrease in the movement of magnetic domain walls during magnetization, resulting in a larger energy required for magnetic domain rotation, which leads to a decrease in the magnetic properties of Co1-xCdxCr2O4. The main goal of the study mentioned in the introduction of the document is to synthesize Cd-doped CoCr2O4 (Co1-xCdxCr2O4) magnetic nanoparticles using a solution combustion method and systematically investigate the effects of Cd ion doping on the phase structure, microstructure, and magnetic properties of the material. The research aims to understand how varying Cd ion concentrations influence lattice parameters, crystallite size, and magnetic characteristics, with the ultimate objective of optimizing the material's magnetic properties for potential applications in magnetic storage media, transformers, inductors, and other magnetic devices.

Utilizing reactive DC magnetron sputtering method, TiN coatings were deposited on the silicon substrates at different nitrogen flows and powers. A study of the X-ray phase composition of the coatings was carried out. The stoichiometric composition of the coatings was determined using energy dispersive x-ray spectroscopy. The structure of the surface, cross-section, and thickness of the coatings were determined using scanning electron (SEM) and atomic force microscopy (AFM). A significant change in the surface structure of TiN coatings was established with changes in deposition power and nitrogen flow. SEM images of cross-sections of all coated samples showed that the formation of coatings occurs in the form of a columnar structure with a perpendicular orientation relative to the silicon substrate. The mechanical properties (elastic modulus E and microhardness H) of TiN coatings of the first group demonstrate a maximum at a nitrogen flow of 3 sccm and are 184 ± 11 GPa and 15.7 ± 1.3 GPa, respectively. In the second group, the values of E and H increase due to a decrease in the size of the structural elements of the coating (grains and crystallites). In the third group, E and H decrease. Microtribological tests were carried out in 4 stages: at a constant load, multi-cycle for 10 and 100 cycles, and with increasing load. The coefficient of friction (CoF) and specific volumetric wear ω depend on the roughness, topology, and mechanical properties of the resulting coatings. Fracture toughness was determined using nanoscratch and depends on the mechanical properties of TiN coatings. Within each group, coatings with the best mechanical and microtribological properties were described: in the first group—TiN coating at 3 sccm (with (29.6 ± 0.1) at.% N), in the second group—TiN coating at 2 sccm (with (40.8 ± 0.2) at.% N), and in the third group—TiN coating at 1 sccm (c (37.3 ± 0.2) at.% N).

The effect of cerium (Ce3+) on the structural, microstructural, Fourier infrared spectroscopic, electrical, and humidity sensing behavior of CoCr2−xCexO4(CoCrCe) is reported in this paper. To prepare the samples, Solution combustion method using mixture of urea and glucose as a fuel. Samples are sintered for 600 °C for 3 h to get single phase. To analyses the creatinine nature and morphology, samples were characterize X-ray diffraction (XRD) and scanning electron microscopy. XRD reveals that formation of cubic spinel structures with typical crystallite sizes of less than 10 nm. When Ce3+ ions are replaced by Cr3+ ions, the lattice parameter found decreases from 8.3289 to 8.3163 Å. This is due to the creation of a compressive lattice strain and may be due to the differences between ionic radius of Ce3+ as compared to Cr3+. We discovered the chrommate structure in the absence of impurities by analysing the octahedral and tetrahedral stretching bands using Fourier infrared spectroscopy. Scanning Electron microscopy results reveals that samples exhibits highly porous nature. Elemental analysis were confirms the Ce3+ is present in the samples. All samples subjected to study the humidity sensing studies. The relative humidity influences the resistivity of the surrounding air significantly. We also investigated the relative permittivity characteristics, the conductivity of the samples of interest, and the capacitive sensor’s response time at a fixed frequency of f = 1 kHz. Further, The variation of both relative permittivity and electrical resistivity were strongly depending on humidity. As concentration of Ce3+ increases the permittivity (unit less), Conductivity, electrical capacity(normalized), Response time of capacitive sensor were found increases such as 150, 108 [Ω m], 10, 90 this is may be due to the larger ionic radius of the Ce3+ and also may be high porosity of the samples. Ce3+ at 2 mol

The article presents a comprehensive investigation of the crystal structure, impedance spectra, magnetic, magnetodielectric, and magnetoresistive properties of (1-x)CoFe2O4-xPbTiO3 composites with varying concentrations (& khcy; = 0, 0.2, 0.4, and 0.6). The study also examines the effects of applying a uniaxial pressure of 1 GPa to the synthesized powders using Bridgman anvils. Our findings reveal that the synthesis of these composites results in the formation of an additional phase, lead hexaferrite PbFe12O19, which exhibits multiferroic properties. Additionally, the coherent scattering region of the components is significantly reduced after mechanical activation. Notably, the real part of the resistivity rho '(omega) of nanostructured CoFe2O4 ceramics increases eightfold at T = 240 degrees C. The composites demonstrate significant magnetoresistance at room temperature, reaching up to 250 %. The study also reveals that the signs of the magnetodielectric MD(B) and magnetoresistive coefficient MR(B) vary with the frequency of the measuring field for certain concentrations. Using the first-order reversal curve (FORC) method, it was observed that after nanostructuring CoFe2O4 through mechanical activation, the interaction field Hu shifts from +/- 0.6 kOe to +/- 0.8 kOe, while the coercive field Hc increases from 1.05 kOe to 5 kOe. Moreover, the two-dimensional FORC maps of the composites show increased complexity, due to the formation of additional magnetic phases.

In this work, the concentration dependencies of unit cell parameters, microstructure, dielectric, impedance spectra, and magnetic properties of (1 – x)SmFeO3–xNaNbO3 were studied for the first time. It was found that at a concentration x = 0.7, the unit cell parameter a, the tilt angles θ and rotation angles φ of oxygen octahedra and the bond lengths Fe-O1 and Fe-O3 of samarium ferrite SmFeO3 (SFO) have a maximum, and Fe-O2 has a minimum value. The tilt angle θ, rotation angle φ of the octahedral, and the bond lengths of sodium niobate NaNbO3 (NNbO) change nonmonotonically. For x = 0.9, the unit cell parameters b and c, as well as all bond lengths in the NaO9 tetradecahedra, reach their minimum values. Anomalies corresponding to the spin-reorientation transition temperatures TSR1 and TSR2 were detected in the dielectric spectra of SFO at temperatures of 200 and 309 °C. The jump in the real part of the dielectric constant ε′(T), starting before – 100 °C, is attributed to the response of the dipole moments to the magnetic moment jump and spin switching (TSSW). Anomalies corresponding to transitions between different phases in this antiferroelectric were found in the temperature dependences of ε′(T) and dielectric loss tangent tgδ(T) of NNbO at temperatures of – 75, 23, 160, 278, 379, and 433 °C. From magnetic measurements, it was found that the composition with x = 0.8 has a minimum size of coherent scattering regions of D = 94 nm, representing the second critical size at which the coercive field Hc reaches its maximum value.

This paper presents the results of studying the structural features and physical properties of two-component composites (1-x)PbFe12O19–xPbTiO3, obtained from pre-synthesized and mechanically activated powders. To control the physical properties of composites, in addition to changing the dopant (PbTiO3) concentration within the range of 0.2–0.8 in steps of 0.2, the method of mechanical activation (nanostructuring) was used. This method implies that the Bridgman anvils simultaneously apply a compressive force to the powder placed between them and produce a shear deformation by rotating the lower anvil. X-ray diffraction revealed a sharp decrease in the unit cell parameters of the dopant of the initial composition at x = 0.4, followed by a similarly sharp leap in the parameters of the hexagonal cell after mechanical activation. The dimensions of the coherent scattering regions (D) of the PbFe12O19 component after mechanical activation decreased by more than a half, while the dislocation density (ρD) and the magnitude of microstrains (ε) increased by more than an order of magnitude. It was found that the magnetic phase transition temperature of composites decreases by about 14 °C with increasing dopant concentration, and the nanostructuring of composites leads to a further decrease in the transition temperature by another 12–36 °C, depending on the dopant concentration. The band gap Eg of the nanostructured compositions increases by approximately 0.3 eV regardless of the dopant concentration. Using the impedance spectroscopy method, it has been discovered that the dependence of the grain capacitance Cg(T) in the temperature range of 150–350 °C has a bell-shaped form, which is explained in terms of Maxwell–Wagner polarization, where the relaxation is of the non-Debye type.

The x BiFeO 3 – (1 – x )PbZr 0.9 Ti 0.1 O 3 composites synthesized by the solid-phase reaction were characterized using complex methods to determine their structure and physical properties. According to the results of X-ray diffraction analysis, it was found that the synthesized composites have a rhombohedral perovskite structure with the space symmetry group R3с , and there are no impurities or second phases present in either the ferrite or ferroelectric phases. According to the results of impedance spectroscopy, it was found that the nature of the relaxation in the composites is non-Debye, suggesting a complex conduction mechanism involving multiple relaxation processes. With an increasing proportion of ferroelectric PbZr 0.9 Ti 0.1 O 3 (PZT) phase, the composites exhibit dual-arc behavior in the Cole-Cole diagrams obtained from the impedance spectroscopy measurements. The dual-arc behavior shows the contribution of both the bulk (grain) and grain boundary to the conduction mechanism in the temperature range of 160–230 °C. The dynamics of the crystal lattice in the composites were studied using optical and FTIR spectroscopy. The magnetization curves M ( H ) of the composites are characterized by weak ferromagnetism, which is due to the substitution of (Ti/Zr) 4+ by Fe 3+ in the crystal lattice. This substitution leads to structural distortions and the appearance of ferromagnetic ordering in the composite materials.

For the first time, the influence of Cerium (Ce3+) on the structural, microstructural, Fourier infrared spectroscopy, and LPG sensing behaviour of CoCr2-xCexO4 (CoCrCe) is described in this study. The solution combustion technique was used to create the CoCrCe samples. All samples were sintered for 3 h at 600 °C to achieve a pure crystalline nature free of impurities. The production of cubic spinel structures with typical crystallite sizes smaller than 16 nm is confirmed by X-ray diffraction. Because compressive lattice strain is created when Ce3+ ions are replaced by Cr3+ ions, we discovered reducing the lattice parameter. Further samples were analysed using the FTIR technique to learn about the octahedral and tetrahedral stretching bands, which confirmed the ferrite structure was free of impurities. Scanning Electron microscopy was used to examine the samples' microstructures. All of the samples were determined to be very porous. Elemental analysis was performed using energy dissipative spectra, which confirmed the presence of all elements in the samples. 2-mol% Ce3+ has the best gas sensing characteristics of any Ce concentration. Furthermore, the thin film based on CoCr1.98Ce0.02O4 may be employed as a chemiresistive gas sensor to detect LPG (10–1000 ppb) at room temperature. On LPG exposure, the constructed gas sensor demonstrates greater gas sensitivity in the order of 98% at 500 ppb, with higher stability, rapid response, and recovery time in the order of 60 s and 75 s, respectively. This study reports for the first time on the creation of an LPG gas sensor device that operates at room temperature and has high sensitivity. Because of their high gas sensitivity, rapid reaction and recovery times, and long-term stability, these material gas sensors might be ideal materials for the manufacture of gas sensors devices for the detection of LPG low concentration (ppb level).

In this work, the structural phase state and physical properties of YbMn1-xFexO3 (hereinafter YbMF) ceramics in the range of x = 0.0–1.0 with a concentration step Δx = 0.1 were studied by complex methods. X-ray diffraction revealed that the YbMF compositions in the range of x = 0.1–0.5 were hexagonal (H) phase solid solutions. In the concentration range of x = 0.6–0.8, the hexagonal and orthorhombic (O) systems coexist, and the unit cell parameters of these phases rise with increasing x. The study of the lattice parameters, bond lengths, bond angles and the main parameters of the magnetic hysteresis loop of the H-phase revealed the presence of a singular point x = 0.5 in the concentration range, where extrema of the corresponding parameters were observed. By analyzing the Cole–Cole plots for the electric modulus M*(ω), a conclusion was drawn about the thermally activated nature of the dielectric relaxation for each composition with a single relaxation time τ. The magnetodielectric MD(ω) and magnetoresistive MR(ω) coefficients measured in crossed and parallel fields E and H show high values, which reach 1.6% and 50%, respectively, depending on the frequency of the measuring field.

The present study investigates the concentration dependence of physical properties and structural parameters of YbMn 1− х Fe х O 3 (YbMF) compositions, which were nanostructured using the mechanical activation method at a pressure of 1 GPa. Using X-ray diffraction, the dependence of the unit cell parameters of the H-hexagonal ( P6 3 cm ) and O-orthorhombic ( Pnma ) phases on the Fe 3+ dopant concentration was studied. It was found for the first time that a morphotropic region (MR) was formed in YbMF in the concentration range x = 0.6–0.8, characterized by the coexistence of H and O-phases. At the point х = 0.5, the minimum values of all bond lengths of the H-phase were observed, while at х = 0.8, the bond length minimum of the YbO 8 dodecahedra of the O-phase was observed. The tilt θ° and rotation φ° angles of oxygen octahedra MnO 6 /FeO 6 of the O-phase also vary with the Fe 3+ concentration in the range of (19.354–19.754)° and (12.648–12.677)°, respectively. Using the complex impedance method Z* = Z ′( ω ) − j·Z″ ( ω ), the study showed that the relaxation character was non-Debye. Theoretical and experimental curves were obtained for each YbMF composition at different temperatures, along with the corresponding equivalent circuits. The study also investigated the parameters of the stochastic magnetic domain structure using the random magnetic anisotropy model. It was found that in the region of solid solutions of YbMF, the values of H c and M r have maxima at x = 0.5, and the highest value of H c , equal to 452 Oe, is inside the MR.

The present study investigates the concentration dependence of physical properties and structural parameters of YbMn1−хFeхO3 (YbMF) compositions, which were nanostructured using the mechanical activation method at a pressure of 1 GPa. Using X-ray diffraction, the dependence of the unit cell parameters of the H-hexagonal (P63cm) and O-orthorhombic (Pnma) phases on the Fe3+ dopant concentration was studied. It was found for the first time that a morphotropic region (MR) was formed in YbMF in the concentration range x = 0.6–0.8, characterized by the coexistence of H and O-phases. At the point х = 0.5, the minimum values of all bond lengths of the H-phase were observed, while at х = 0.8, the bond length minimum of the YbO8 dodecahedra of the O-phase was observed. The tilt θ° and rotation φ° angles of oxygen octahedra MnO6/FeO6 of the O-phase also vary with the Fe3+ concentration in the range of (19.354–19.754)° and (12.648–12.677)°, respectively. Using the complex impedance method Z* = Z′(ω) − j·Z″ (ω), the study showed that the relaxation character was non-Debye. Theoretical and experimental curves were obtained for each YbMF composition at different temperatures, along with the corresponding equivalent circuits. The study also investigated the parameters of the stochastic magnetic domain structure using the random magnetic anisotropy model. It was found that in the region of solid solutions of YbMF, the values of Hc and Mr have maxima at x = 0.5, and the highest value of Hc, equal to 452 Oe, is inside the MR.

Coatings based on cobalt-manganese spinel (Mn, Co)·(Mn, Co)2O4 were obtained on the surface of stainless steel by polarization with alternating asymmetric current. The study of the mechanical properties showed that the coatings are characterized by a sufficiently high adhesion to the substrate, their thickness is about 30 μm, and the microhardness value is 40 HV, which is comparable to similar oxide materials. The study of thermal stability in air shows their stability at temperatures up to 1000 °C, and the study of corrosion-protective properties - about the stability of the resulting coatings in a solution of 3.5% (wt.) NaCl.