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Binary and ternary composites based on soft magnetic spinels CoFe 2 O 4 (or CFO) and Ni 0.4 Cu 0.2 Zn 0.4 Fe 2 O 4 (or NCZFO) were produced. Binary CFO/NCZFO ceramic composite was consist of two magnetic phases with 1:1 ratio. Ternary CFO:FEP, NCZFO:FEP and [CFO/NCZFO]:FEP composites were produced by the thermal pressing of the initial ceramic powders (20 wt%) and fluorinated ethylene propylene – FEP (80 wt%). XRD, SEM and VSM investigation were carried out. The impact of the chemical composition and phase ratio of the composites on crystal structure, microstructure and magnetic properties were established. Magnetic measurements were performed at 300 and 10 K in the fields up to 70 kOe. It was demonstrated the synergetic effect for ceramic composite with the violation of the principle of additivity in two-phase ceramic composites. • Binary and ternary composites based on spinels and polymer (FEP) were produced. • Correlation between composition, structural parameters and magnetic properties was established. • It was demonstrated the synergetic effect with the violation of the principle of additivity. [ABSTRACT FROM AUTHOR]

The gallium-doped pure barium hexaferrite (BaFe 12-x Ga x Ο 19) with different concentration (x ≤ 2) was investigated by using neutron powder diffraction (NPD) carried out at various temperatures for studying the magnetic structures according to the crystal structure. A comparison between x-ray diffraction (XRD) and neutron powder diffraction (NPD) are investigated. Some differences between XRD and NPD were observed and explained by the hybridization of electronic shells in complex oxides. The atomic coordinates, as well as lattice parameters, are explained according to Rіetveld processed. The improve associated with the micro-strain value along with the lowering temperature can descrіbe through Rіetveld refinement. A model for the magnetic structure is proposed where the most possible factors and mechanism with the magnetic structure formation are discussed. • The gallium-doped barium hexaferrite have been prepared by conventional solid reaction method. • Characterization by using neutron powder diffraction. • Comparison between X-ray diffraction and neutron powder diffraction. • Crystal and magnetic structure of the prepared samples were investigated. [ABSTRACT FROM AUTHOR]

Abstract M-type hexagonal ferrites with heterovalent substitutions (Nd3+-Zn2+ and Ti4+) were synthesized. X-Ray diffraction (XRD) powder patterns of Sr(Nd,Zn) x Fe 12-x O 19 and BaFe 12-x Ti x O 19 (0.1 ≤ x ≤ 1.0) confirmed the single phase constitution of all investigated samples. High frequency magnetic (permeability), electrical (permittivity), and resonant properties were analyzed. Unexpected behavior in the permittivity and permeability as a function of frequency was observed. Appearance of two peaks for samples with x = 0.1 and 0.9 indicated mixed oxidation state for the Fe ions. Behavior for Sr(Nd,Zn) x Fe 12-x O 19 (0.3 ≤ x ≤ 0.7) confirms the occurrence of the anomalous quantum effect, namely charge disproportionation. The permeability behavior of Ti-substituted samples with a double Fe oxidation state was theoretically discussed in terms of spin states crossover. The behavior of reflection losses for Sr(Nd,Zn) x Fe 12-x O 19 and BaFe 12-x Ti x O 19 (0.1 ≤ x ≤ 1.0) samples was discussed in terms of the modalities of charge ordering in heterovalent substituted M-type hexaferrites. Highlights • Heterovalent substituted M-type hexaferrites were synthesized and investigated. • Double oxidation states for Fe ions were established. • Electrodynamics characteristics were explained based on quantum effects. [ABSTRACT FROM AUTHOR]

Present paper describes systematic studies of the functional BaFe 12-x DI x O 19 (DI = Al 3+ , In 3+ 0.1 ≤ x ≤ 1.2) solid solutions. Correlation between the fine atomic structure and intrasublattice Fe 3+ - O 2− - Fe 3+ superexchange interactions were explained using precision neutron powder diffraction and Mossbauer spectroscopy. Critical influence of the diamagnetic Al 3+ and In 3+ ions on electromagnetic properties in substituted Ba-hexaferrites (M-type) was discussed. Transmission spectra demonstrated a deep minimum in the frequency range 20–65 GHz due to natural ferromagnetic resonance (NFMR). Increase of the Al 3+ ions concentration shifted the resonance frequency from 51 GHz to 61 GHz. Increase of the In 3+ ions shifted the resonance frequency from 50.5 GHz to 27 GHz. Data of the numerical calculations and experimental results correlates well. It has been demonstrated that external magnetic fields critically influence on electromagnetic properties due to increase of magnetic anisotropy. This opens broad perspectives for practical applications. [ABSTRACT FROM AUTHOR]

The investigations of the crystal and magnetic structure by powder neutron diffractometry as well as the magnetic properties by vibration sample magnetometry for the BaFe 11.9 In 0.1 O 19 polycrystalline sample have been performed in a wide temperature range from 10 K up to 730 K and in the magnetic fields up to 14 T. The atomic coordinates and lattice parameters have been Rietveld refined. The Invar effect has been observed in low temperature range below 150 K. The temperature evaluation of the main Fe O bond lengths and Fe O Fe bond angles are constructed. The increase of microstress value with decreasing temperature has been defined from Rietveld refinement. From the microscopic diffraction measurement the magnetic moments at different atomic position and total magnetic moment per iron ion have been defined at different temperatures. The nature of the intrasublattice and intersublattice Fe 3+ O 2− Fe 3+ indirect exchange interactions is investigated at the different temperatures. From the macroscopic magnetization measurement the Curie temperature and the ordered magnetic moment per nominal iron ion are obtained. It is established that the ferrimagnet-paramagnet phase transition is a standard second-order one. The magnetic structure model is proposed. The most likely reasons and the mechanism of magnetic structure formation are discussed. [ABSTRACT FROM AUTHOR]

• In-substituted SrM hexaferrites were synthesized using solid state reactions. • Coexistence of the electrical and magnetic ordering at room temperature was observed. • Formation of the bevelled magnetic structure was no detected. • The reason of the ferroelectricity was discussed in the frame of P 6 3 mc space group. The local crystal/magnetic structures of the SrFe 12−x In x O 19 solid solutions (x = 0.1; 0.3; 0.6 and 1.2) were investigated using neutron powder diffraction. The measurements of the electric polarization for all investigated samples were carried out as a function of the external electric field. The presence of the ferroelectric and ferromagnetic ordering (dual ferroic ordering) in the SrFe 12−x In x O 19 hexaferrites at 300 K was found. This appearance contradicts to the conventional opinion describing their crystal structure (centrosymmetric space group P 6 3 /mmc (No. 194)). The reason for the existence of a spontaneous polarization (nonzero dipole moment) in the SrFe 12−x In x O 19 hexaferrites continues controversial. The crystal structure of the hexaferrites was considered both the centrosymmetric P 6 3 /mmc and non-centrosymmetric P 6 3 mc space groups. This fact made it possible to find a connection between the emerging dipole moment and not equal distortions of the neighbor oxygen polyhedral. The nature description of the nonzero dipole moment formation in a quasi-centrosymmetrical system of the In-substituted SrFe 12−x In x O 19 hexaferrites was presented based on the neutron diffraction data. [ABSTRACT FROM AUTHOR]

Present paper reports about the strong correlation of the heat treatment conditions (annealing), crystal structure parameters, microstructure and magnetic properties evolution in nanosized BaFe 12 O 19 M-type hexaferrites or BaM nanohexaferrites. Samples of the BaM nanohexaferrites were obtained using sol-gel method with further annealing in the range 600–1100 °C. All investigated samples were single phase and described by the P 6 3 / mmc space group. Unusual and non-linear behavior of the lattice parameters with annealing temperature increasing from 600 to 1100 °C was explained by the competition of the increase in the average crystallite size (decrease in the surface tension effect) and increase in the level of their chemical homogeneity (anionic stoichiometry). Increase of the heat treatment temperature leads to increase of the microstructure parameters (average crystal size and specific surface area) and non-linear changes in magnetic properties. Correlation of the annealing temperature and magnetic properties was discussed in terms of the structural features. • BaM nanohexaferrites were synthesized using sol-gel method with further annealing. • Strong correlation between average crystal size and annealing temperature was established. • Non-linear behavior of the structure and magnetic properties after annealing was observed. • All changes in BaM were discussed in terms of the morphology evolution. [ABSTRACT FROM AUTHOR]

The Dy-substituted Co 1/2 Ni 1/2 (Fe 2-x Dy x)O 4 (0.00 ≤ x ≤ 0.08) spinels were obtained in nanosized form. Correlation between chemical composition, crystal structure, magnetic properties and electrodynamics properties was investigated. The features of the fine crystal structure were investigated using neutron powder diffraction. Magnetic properties were studied utilizing vibration sample magnetometry in the wide temperature and magnetic field ranges. Electrodynamic properties were measured in high-frequency range of 2–18 GHz using vector network analyser. This data was used for reflection losses calculations. There was observed high resonant reflection in the range of 2–6 GHz due to electromagnetic radiation absorption. The weakening of the reflected radiation was explained by the domain boundary resonance. This explanation correlates well with the data of the microstructure analysis. The nature of absorption due to domain boundary resonance in low dimensional magnetic oxides was given. A strong correlation between the level of chemical substitution and amplitude-frequency characteristics for investigated Co 1/2 Ni 1/2 (Fe 2-x Dy x)O 4 (0.00 ≤ x ≤ 0.08) spinels was detected. • Nanosized Dy-substituted Ni–Co spinels were synthesized using sol-gel method. • Strong correlation between composition and microstructure was observed. • Behaviour of the magnetic properties was analysed in terms of the magnetic structure frustration. • Reflection losses correlates well with composition and crystal size distribution. • The weakening of the reflected radiation was explained by the DBR. [ABSTRACT FROM AUTHOR]

The peculiarities of the fine atomic and magnetic structure, magnetic properties and microwave characteristics under Sc-substitution were investigated in Ba(Fe 1-x Sc x) 12 O 19 (x ≤ 0.1) solid solutions. Structural data was obtained using neutron powder diffraction with high resolution on atomic level and was described in the frame of standard P6 3 /mmc Space Group. Almost linear increase of the main lattice parameters and internal stress was explained by the difference in ionic radius of Fe3+ and Sc3+. Magnetic properties were determined by VSM and discussed in terms of Mossbauer studies. The non-linear behavior of the magnetic parameters was explained by the features of Sc3+ ions distribution in the hexaferrite structure and some deviation from strict collinearity in the direction of the magnetic vector. Concentration dependence of coercivity in the concentration range x ≥ 0.05 was explained by rapid frustration of the magnetic structure (destruction of the magnetic long range ordering due to weakening of the intrasublattice exchange interaction in Fe3+-O2--Fe3+ in the first and second coordination spheres). Microwave properties were investigated using a co-axial method in the high frequency range (20–60 GHz). It has been demonstrated that the nature of electromagnetic absorption in Ba(Fe 1-x Sc x) 12 O 19 (x ≤ 0.1) solid solutions is caused by natural ferromagnetic resonance. A good correlation was established between the theoretical calculation of the resonant frequency and the experimental results. It opens broad prospects for practical applications of substituted hexaferrites at higher frequencies. • Lightly-doped Ba(Fe 1-x Sc x) 12 O 19 (x < 0.1) ceramics were synthesized using solid state reactions. • Strong correlation between Sc3+ concentration and diamagnetic ions distribution was observed. • Control of the high frequency properties of the Ba(Fe 1-x Sc x) 12 O 19 (x < 0.1) ceramics was demonstrated. • Non-linear magnetic and microwave properties was explained by the features of magnetic structure. [ABSTRACT FROM AUTHOR]

Crystal structure of the Bi 1-x Ba x Fe 1-x Ti x O 3 ceramics across the phase boundary region between the polar rhombohedral and pseudo-cubic phases has been investigated by means of X-ray and neutron diffraction, scanning electron microscopy and differential scanning calorimetry techniques. The structural measurements have revealed a decrease in the rhombohedral distortions upon increase in the dopant content followed by the stabilization of the pseudo-cubic phase at x ≥ 0.20. While temperature increase gives rise to the similar pattern of structural changes for the lightly-doped samples, an unpredictable temperature-driven strengthening of the rhombohedral distortions has been found for the compounds belonging to the phase boundary region. The study specifies the peculiarities of the temperature-driven evolution of the crystal structure depending on the structural state of the compounds at room temperature. • Evolution of the crystal structure is studied as a function of the dopant content and temperature. • An unpredictable temperature-driven strengthening of the rhombohedral distortions has been found for the compounds at MPB. • a non-vertical character of the temperature phase boundary and non-monotonous change of the phases ratio have been revealed. [ABSTRACT FROM AUTHOR]

In this study, magnetic, structural, and hyperfine interactions of Sc3+ ion substituted Sr 0.5 Ba 0.5 Fe 12 O 19 (Sr 0.5 Ba 0.5 Sc x Fe 12−x O 19 (x ≤ 0.1)) nanohexaferrites (Sc→SrBa NHFs) have synthesized through the sonochemical approach. The structure and morphology were studied by XRD, SEM, HR-TEM, and TEM along with EDX. XRD analysis confirmed the hexaferrite formation having crystallite within the range of 45 to 79 nm. Both TEM, HR-TEM, and SEM analyses proved the hexagonal morphology of all products. All products show ferrimagnetic hysteresis loops at both Ts. The evaluation of M(H) hysteresis loops indicated that the M s (saturation magnetization), M r (remanence), H c (coercivity), and n B (Bohr magneton number) gradually decline with the incorporation of Sc3+ ion. Higher doping contents (x ≥ 0.08) revealed a considerable decline in M r and H c , showing significant changes from hard to soft magnetic behavior at higher contents. Mössbauer spectra show that Sc3+ ions are located at commonly octahedral (Oh) 4 f 2 site. It was also determined that a small amount of Sc3+ occupied the 2b site. The microwave features of the products were determined by measuring S-parameters within the 2–10 GHz range. It was presumed that the energy losses resulting from reflection encompass both electrical and magnetic loss components. The average value of the reflection coefficient is − 14.48–14.24 dB. A noteworthy attenuation of the reflected wave energy opens up broad prospects for practical applications as coatings for providing electromagnetic compatibility. • Sr 0.5 Ba 0.5 Sc x Fe 12−x O 19 (x ≤ 0.1)) nanohexaferrites were synthesized via sonochemical approach. • XRD powder patterns confirmed the formation M-type hexaferrites. • All products show ferrimagnetic hysteresis loops at room and 10 K. • The average value of the reflection coefficient is − 14.48-14.24 dB. • A noteworthy attenuation of the reflected wave energy opens up broad prospects for practical applications as coatings for providing electromagnetic compatibility. [ABSTRACT FROM AUTHOR]

M-type Ba 0.5 Sr 0.5 Co x La x Fe 12-2 x O 19 hexagonal ferrite has been synthesized by the conventional ceramic method. X-ray diffraction analysis confirmed formation of M-type hexagonal structure while scanning electron microscopy analysis revealed a reduction in grain size with the doping of Co2+ and La3+ ions. The electromagnetic/microwave absorption has been measured from 8.2 GHz to 12.4 GHz in the microwave frequency regime and substantiated through hysteresis parameters, quarter wavelength, impedance matching, loss mechanisms. The hysteresis parameters, derived from hysteresis loops, infer soft ferrite nature of compositions. The doping of Co2+ and La3+ decreases coercivity to 17 Oe in composition x = 0.2 and increases saturation magnetization to 74.2 emu/g in composition x = 1.0. The doping improves impedance matching and increases microwave absorption as well as absorption bandwidth in the prepared compositions. The pronounced multi-peaks of absorption have been observed in composition x = 0.2 and 0.4 in the investigated frequency region. The depicted reflection loss dips are tunable through doping and thickness of the compositions. The reflection loss increases to −43.33 dB in composition x = 0.2 at 10.75 GHz and 1.9 mm thickness. The composition x = 0.2 also shows −10 dB and −20 dB narrow absorption bandwidth of 300 MHz and 320 MHz respectively. • Ba 0.5 Sr 0.5 Co x La x Fe 12-2 x O 19 ferrite has been prepared by ceramic method. • Effect of doping on structural, hysteresis and microwave absorption has been studied. • Composition x = 0.2 has absorption of −43.33 dB at 10.75 GHz and 1.9 mm thickness. • Coercivity reduced to 17 Oe in x = 0.2 and saturation magnetization increased to 74.2 emu/g in x = 1.0. • -10 dB wide bandwidth of 2.65 GHz and narrow bandwidth of 300 MHz is observed in x = 0.6 and 0.2 respectively. [ABSTRACT FROM AUTHOR]

Ni nanopillars (Ni NPs) composite material formation technology embedded in porous anodic alumina by electrochemical deposition is presented in this paper. The morphological and structural properties of the composite material were investigated using scanning electron microscopy, atomic force microscopy, X-ray diffraction. The corrosion resistance of the nanocomposite materials has been studied by potentiodynamic polarization curves analysis and polarization resistance method. The composite represents the array of vertically ordered Ni NPs with the identical size in alumina matrix. XRD investigation indicates that Ni NPs are polynanocrystalline material with 18 nm crystallite size. It has been shown that Ni NPs and the composite material have sufficient corrosion resistance in a 0.9% aqueous NaCl solution. Porous alumina is the neutral and protective component of the composite. These nanocomposite materials can be excellent candidates for practical use in electronics, sensorics, biomedicine. • Unique technology of anodic alumina matrix formation has been developed. • Composite based on Ni nanopillars in anodic alumina matrix has been produced. • Method for corrosion resistance investigation for nanomaterials has been proposed. • First time corrosion resistance properties for Ni nanopillars have been performed. • Ni nanocomposites show unexpected corrosion resistance properties. [ABSTRACT FROM AUTHOR]

ScIn→Sr NHFs have been synthesized via the sol-gel combustion method. The phase and morphonology were analyzed via XRD, SEM, TEM, and HR-TEM. XRD measurements confirmed the purity of all products having the crystallite size (D XRD) of 31–77 nm obtained via Rietveld refinement. The agglomeration of products was observed in SEM and HR-TEM images due to their magnetic character. SEM images revealed the hexagonal-shaped nanoparticles. Mössbauer spectra showed that In3+ and Sc3+ ions are located at generally octahedral (Oh) 4 f 2 site. The electron density s of iron ions of 4 f 2 and 2a sublattices is affected by doping content. The obtained M-H curves (field-dependence of magnetization) demonstrated ferrimagnetic hysteresis loops at both 300 and 10 K. The analysis of M-H curves also showed that the saturation magnetization (M s) first declined until x = 0.03, then grew up to x = 0.05, and returned to decrease thereafter. The coercivity (H c) decreased sharply with Sc-In substitution, transforming the magnetic character of samples from hard to soft. Microwave (MW) properties were measured and analyzed between 33 and 50 GHz. It was demonstrated that the increase of the Sc3+/In3+ concentration led to modifications in amplitude-frequency characteristics of the electromagnetic absorption process. It was shown that Sc3+/In3+ substituted Sr NHFs can be used for developing radioelectronic coatings and providing electromagnetic compatibility. • Sc3+/In3+ substituted Sr hexaferrites for electromagnetic compatibility. • In3+ and Sc3+ ions are located at generally octahedral (Oh) 4 f 2 site. • Ferrimagnetic hysteresis loops at 300 and 10 K. • Modifications in amplitude-frequency properties of the electromagnetic absorption. [ABSTRACT FROM AUTHOR]

The Co-V co-substituted nano Sr-hexaferrite, Sr 0.5 Co 0.5 V x Fe 12−x O 19 (0.00 ≤ x ≤ 0.08) (V→SrCo (0.00 ≤ x ≤ 0.08) NHFs), were manufactured by citrate combustion route. The microstructure, morphology, magnetic features, hyperfine interactions and oxidation state and chemical composition of products explained by XRD, SEM with EDX, HR-TEM, VSM, Mossbauer spectrometry, and XPS, respectively. The D XRD (Average crystallite size) of products were assessed via Scherrer formula as within the range of 37 and 83 nm. The hexagonal morphology and chemical composition of the products was presented by TEM, HR-TEM, SEM and EDX analyses. The XPS analysis provided both the composition and oxidation states of prepared NHFs. Mossbauer spectra showed that the s electron density around Fe3+ ions of all sites except 12k influenced V3+ content. The coercivity data indicates that all samples denote a magnetically hard material at both low and high temperatures. M s , M r and n B fluctuate with respect to dopant concentration and attain their highest magnitudes for the V→SrCo (x = 0.04) NHFs. A SQR of around 0.5 is achieved at each temperature, reflecting a relatively high large anisotropy field. The field-cooling (FC) curves of all samples yield a drop in magnetization with increasing temperature. Their irreversibility temperature is detected to be beyond 325 K. Both M-H and M-T imply the ferrimagnetic behavior of different samples. Microwave properties were measured between 2 and 18 GHz as S11-S21 parameters. It demonstrated non-linear behavior of the microwave properties vs. V concentration. The origin of the reflection losses in NHVs can be explained by the dipole polarization processes. • V co-substituted nano Sr-Cohexaferrite, (V→SrCo (x ≤ 0.08)) NHFs), were manufactured by citrate combustion route. • Magnetic characteristics of V→SrCo NHFs are showed crucial impact of co-doping on SrFe 12 O 19 is exhibited. • Microwave properties were measured between 2 and 18 GHz as S11-S21 parameters. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles based on Fe 3 O 4 and their modifications of surface with therapeutic substances are of great interest, especially drug delivery for cancer therapy includes boron-neutron capture therapy. The results of boron-rich compound (carborane borate) attachment to previously aminated by (3-aminopropyl)-trimethoxysilane iron oxide nanoparticles are presented. Energy-dispersive X-ray analysis and Fourier transform infrared spectroscopy with attenuated total reflection (ATR) accessory confirmed change of nanoparticles elemental content after modification and formation of new bond between Fe 3 O 4 and attached molecules. Scanning and transmission electron microscopy showed that Fe 3 O 4 nanoparticles average size is 18.9 nm. Phase parameters were investigated by powder X-ray diffraction, Fe 3 O 4 nanoparticles magnetic behavior was evaluated by Mössbauer spectroscopy. Chemical and colloidal stability was studied using simulated body fluid (phosphate buffer – PBS). Modified nanoparticles have excellent stability in PBS (pH = 7.4), characterized by X-ray diffraction, Mössbauer spectroscopy and dynamic light scattering. Fe 3 O 4 biocompatibility was elucidated in-vitro using cultured mouse embryonic fibroblasts. The obtained results show the increasing of IC 50 from 0.110 mg/ml for Fe 3 O 4 to 0.405 mg/ml for Fe 3 O 4 -Carborane nanoparticles. Obtained data confirm biocompatibility and stability of synthesized nanoparticles and potential to use them in boron-neutron capture therapy. • Fe 3 O 4 nanoparticles (NPs) with 18.9 nm average size were synthesized and modified with APTMS. • NPs were characterized using FTIR, SEM, TEM, XRD, DLS, Mössbauer spectroscopy and VSM methods. • Modified NPs have excellent stability in simulated body fluid. • Carborane borate with 21 boron atoms was immobilized on NPs through the ionic interaction. • Synthesized modifed NPs are excellent candidates for using in boron-neutron capture therapy. [ABSTRACT FROM AUTHOR]

Abstract The problem of increasing reliability of semiconductor devices under extreme ionizing radiation (electrons, protons, gamma radiation etc.) is relevant. Uses of WCu composite materials with high density and reduced mass-dimension characteristics offer a very attractive alternative to lead protection due to more environmentally friendly composite. W 85 Cu 15 and W 75 Cu 25 composites were obtained by solid-phase synthesis. XRD data showed that the main lines of the WCu spectrum correspond to the body-centered cubic phase of tungsten-copper alloy and the face-centered cubic phase of copper. The W 85 Cu 15 and W 75 Cu 25 composites consist two main phases: W 0,6 Cu 0,4 phase and Cu phase. This may be due to the alloy presence on the outer part of the tungsten grains, which was formed as a result of thermal annealing and copper diffusion during composite synthesis. The most intense peak (110) is maintained when the tungsten concentration changes. The peaks shift towards large angles with a tungsten concentration decreasing in the composite is observed. The intensity of copper peaks increases and a new low-intensity peak appears (220) with the copper concentration increasing in the composite. The shielding properties of the W 85 Cu 15 composite with n- and p -MOS transistors under 1.6÷1.8 MeV electron radiation have been studied. It has been established that maximum shielding efficiency for p -MOS transistors (K a = 143÷155) have shields with 1.2÷1.5 mm thickness. Shields provide the total absorbed dose reduction up to 6 times for outer space protons (energies from 0.04 to 500 MeV for the 60° orbital inclination and a circular orbit with a height of 300 km). Highlights • It has been shown that WCu composites consist three main phases (W,W 0,6 Cu 0, 4 and Cu). • Isostructural W/W 0,6 Cu 0,4 phases ratio critical determines shielding properties. • It has been demonstrated the optimal WCu thickness for best electron protection. • Shields based on W 85 Cu 15 provide a reduction of the proton up to 6 times. [ABSTRACT FROM AUTHOR]

Abstract This is first report on Nd-NbZn co-substituted M-type Ca-Sr hexaferrites with nominal compositions Ca 0.4 Sr 0.6-x Nd x Fe 12.0- x (Nb 0.5 Zn 0.5 ) x O 19 (x = 0.00–0.32) fabricated by the conventional solid-state reaction method. X-ray diffractometer (XRD), Fourier transformer infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), physical property measurement system-vibrating sample magnetometer (PPMS-VSM) were employed to characterize M-type calcium-strontium hexaferrites. XRD patterns of the hexaferrites with Nd-NbZn content (x) of 0.00 ≤ x ≤ 0.16 showed the single M-type hexaferrite phase. However, for the hexaferrites with Nd-NbZn content (x) ≥ 0.24, the impurity phase (α-Fe 2 O 3 ) was observed. FT-IR frequency bands in the range (592–613) cm−1 and (430–470) cm−1 corresponded to the formation of tetrahedral and octahedral clusters of metal oxides in the hexaferrites, respectively. FE-SEM micrographs showed that the grains were platelet-like shapes. The saturation magnetization ( M s ) and magneton number (n B ) decreased with increasing Nd-NbZn content (x) from 0.00 to 0.32. The remanent magnetization ( M r ) first increased with Nd-NbZn content (x) from 0.00 to 0.08, and then decreased when Nd-NbZn content (x) ≥ 0.08. The M r / M s ratio, coercivity ( H c ) and magnetic anisotropy field ( H a ) increased with increasing Nd-NbZn content (x) from 0.00 to 0.32. First anisotropy constant ( K 1 ) first slightly increased with Nd-NbZn content (x) from 0.00 to 0.08, and then decreased when Nd-NbZn content (x) ≥ 0.08. Highlights • First report of studies on Nd-NbZn co-substituted M-type Ca-Sr hexaferrites. • Studied the effects of Nd-NbZn content (x) on the formation of M-type hexaferrite phase. • Magnetic measurements show a significant improvement in coercivity ( H c ). • Established an optimum Nd-NbZn co-substitution content to obtain single phase M-type hexaferrites. [ABSTRACT FROM AUTHOR]

The aim of these work was to investigate low temperature fast synthesis of cobalt spinel ferrite polycrystalline ceramics. The idea of combining high temperature and high pressures was in the possibility of a sharp decrease in the synthesis time by the lowering the threshold for activation of chemical interaction due to increasing the rate of diffusion kinetics. Test samples with 2–3 orders of magnitude less duration and reduced sintering temperature by 400º C comparing to conventional sintering were synthesized from initial oxides using solid state reactions method under high-pressure. The thermobaric conditions (combination of high temperatures and high pressures during synthesis) on phase content, structural properties, magnetic and electrical properties of the CoFe 2 O 4 spinels were also investigated. The synthesis was performed at T = 800 °С under high pressures (P = 1–5 GPa) and duration of 1 min. Evolution of the phase composition, microstructure, magnetic and electrical properties of CoFe 2 O 4 ceramics as function of the synthesis pressure was investigated using XRD, SEM, VSM and impedance spectroscopy respectively. Results of XRD demonstrate the formation spinel-like main phase (SG: Fd-3 m) with impurities. It was observed that average grain size decreased from 661 to 355 nm with P increasing from 1 till 5 GPa respectively. It was observed that the P increase induce the non-linear changes in magnetic properties. Thus, M s decreased from 70,8–60 emu/g while H c and M r had a slight increasing trend with increase P from 1 till 5 GPa. CoFe 2 O 4 samples that were produced under higher pressures demonstrated dramatically higher values of permittivity. The proposed method is perspective way for production of the high-density magnetic ceramics with significantly reduced sintering time in comparison with the traditional solid state reactions method. The modification of the proposed method for control phase composition and physical properties is the goal for further investigations. [Display omitted] • Impact of thermobaric conditions on electrical, magnetic properties of Co-ferrite is studied. • Average grain size decreases from 661 nm to 355 nm with increasing pressure from 1 GPa to 5 GPa. • High permittivity value of 5045 at 120 Hz is obtained at sintering pressure P = 5 GPa. • Saturation magnetization vary from 70,8 to 59,2 emu/g with decreasing pressure. [ABSTRACT FROM AUTHOR]

BaFe 12-x Ti x O 19 (x = 0.5, 1, 2) solid solutions were synthesized by solid state reaction at 1350 °C for pure BaFe 12 O 19 and 1400 °C for Ti-substituted samples for 3 h in the air. The phase purity of the final products was verified by X-ray diffraction. The decrease of Curie temperature of the solid solutions from 450 to 240 °C was induced by x changes from 0 to 2. The electromagnetic parameters of the BaFe 12-x Ti x O 19 (x = 0.5, 1, 2) ferrites were measured in the frequency range of 8–12 GHz using the transmission line method. [ABSTRACT FROM AUTHOR]

The various ionizing radiations (electrons, protons, heavy charged particles, X-ray and gamma radiation) are the damaging factors for microelectronic products. The common used material for radiation protection is lead. Recently, Bi deposition has become an interest for the electrochemical community because of bismuth's unique electrical, physical and chemical properties. There is a limited number of authors dealing with Bi films onto metallic substrates by electrochemical deposition. The electrochemical deposition conditions and Bi coatings structure were examined. X-ray diffraction patterns for all samples were indexed to rhombohedral Bi. Coatings with a signified texture (012) are formed in electrolyte without additives. With gelatin adding the growth texture changes and the most intense reflex becomes (110). It was found that gelatin concentration increasing from 0.1 to 0.5 g/L leads Bi microstructural refinement from 4-20 μm to 50 nm-2 μm, respectively. The protection efficiency of shields based on Bi under 1,6–1,8 MeV electron radiation energy was measured. The electron beam attenuation efficiency was estimated by the changing of current-voltage characteristics of semiconductor test structures which were located behind the shields and without them. It has been determined that optimal protection effectiveness and mass-dimensional parameters have Bi shields with 2 g/cm 2 reduced thickness and 156 attenuation coefficient. [ABSTRACT FROM AUTHOR]

Thin Ni-Fe films were produced via electrodeposition onto silicon substrate using direct current and pulse (with different pulse durations) regimes. The correlation between technological regimes and chemical composition and microstructure for Ni-Fe nanogranular films was discussed. Analysis of the microstructure evolution revealed the changing mechanism of the films growth from the Volmer-Weber (describes island film growth) to the Stranski-Krastanov (layer by layer at the growth beginning) with the shortening of the pulse duration less than 10 μs. This anomalous behavior was explained by an increase of the binding energy between the initial atoms and the substrate surface. The results showed that using electrodeposition regimes, which ensure growth with the average crystal size less than the critical value (10 nm), provides less roughness, defectiveness and greater film uniformity in thickness, and, therefore, stable properties. [ABSTRACT FROM AUTHOR]

The electrodeposition of Bi films from an acid perchlorate electrolyte was examined. The influence of various factors on the process of bismuth electrodeposition was investigated. It was determined that electrolyte mixing, temperature, organic additives exert a noticeable influence on the electrode process of the discharge of Bi 3+ ions in acid perchlorate electrolyte. X-ray diffraction patterns for all samples were indexed to rhombohedral Bi. Coatings with a signified texture (012) are formed in electrolyte without additives. This texture is retained by adding into the electrolyte the organic additives such as cresol, resorcinol, synthanol. With coloring agents (acridine yellow and safranin violet), the growth texture changes and the most intense reflex becomes (110). SEM investigations of coatings surface morphology showed that films electrodeposited without additives, as well as with safranin coloring agent, eventually form crystalline films with a block size of tens of microns, but with different texture growth. The additional presence of such organic additives as syntanol and resorcinol in the electrolyte guarantees flat, dense, close grained and uniform coatings with a thickness of 600 μm at room temperature and the highest cathode current density. [ABSTRACT FROM AUTHOR]

As produced glass-coated ferromagnetic microwires typically have an amorphous state and demonstrate ultra-soft magnetic properties. For many applications, microwires with strong hard magnetic properties are of interest. A giant increase in coercivity has been recently reported for microwires subjected to directed crystallization. This paper confirms the coercivity increase up to 42 kA/m for wires of composition Fe 4.3 Co 67.7 Si 11 B 14 Cr 3 after magnetic-field assistant directed crystallization. To understand the effect of the directional crystallization on wire magnetic properties and to develop the reliable annealing technology the structural and mechanical transformation occurring during various stages of the annealing processes were investigated. [ABSTRACT FROM AUTHOR]

Structural, electronic, optical, thermoelectric and magnetic properties of A 3 In 2 As 4 and A 5 In 2 As 6 (A = Eu and Sr) Zintl phase compounds in orthorhombic (Pnma and Pbam) phases are examined using density functional theory. Structure properties are an agreement with the experiment. Magnetic properties disclose the Non-magnetic nature of Sr 3 In 2 As 4 and Sr 5 In 2 As 6 and anti-ferromagnetic nature of Eu 3 In 2 As 4 and Eu 5 In 2 As 6 compounds.Electronic properties of Sr 3 In 2 As 4 , Sr 5 In 2 As 6 and Eu 3 In 2 As 4 , Eu 5 In 2 As 6 shows that all these compounds have narrow direct bandgap semiconductors at ᴦ and M symmetry. Electrical conductivity also gives the information about the semiconducting characteristic of these compounds. These compounds show that reduction in bandgap occurs through the substitution of Sr by Eu while increasing by going from local density approximation to modified Becke-Johnson potential and further reduce by spin orbit coupling effect. The outcome demonstrates that all compounds are optically dynamic in the infrared region, anisotropic and obstruct ultraviolet waves so these compounds are capable to use as shield for ultraviolet radiation and can be used as paramount applicant for optoelectronic devices. Owing to low thermal conductivity, high Seebeck coefficient, power factor and Figure of merit ranges from 0.39 to 1.2 at 800 K indicating that all compounds are active aspirants for thermoelectric applications. • Structural, electronic, optical, thermoelectric and magnetic properties of the Zintl phase compounds are examined using DFT. • Good agreement DFT results and experiment was obtained. • Nonmagnetic nature of Sr 3 In 2 As 4 , Sr 5 In 2 As 6 and antiferromagnetic nature of Eu 3 In 2 As 4 , Eu 5 In 2 As 6 compounds was revealed. • It is shown that all substances are optically anisotropic, active in the IR-region and block UV-waves. • Such materials can be applied as shields for UV-radiation and paramount applicant for optoelectronic devices. [ABSTRACT FROM AUTHOR]

• Correlation of Sn-content in BaM hexaferrites, phase composition and MW properties was observed. • Impact of heterovalent substitution on M s and H c was discussed. • High electromagnetic absorption was achieved in 2–4 GHz frequency range. • More than 99.9% of the incoming electromagnetic radiation was absorbed. Hexaferrites are usually used in devices for frequencies of 8–75 GHz. In this work, it is shown that Sn-substituted hexaferrite can be used for electromagnetic shielding and at lower frequencies (for example, in the L -band and S-band) as absorbing materials. The paper defines a solid-state reaction technique for preparing BaFe 12−x Sn x O 19 (0.1 ≤x ≤ 1.2). The samples are characterized by XRD, SEM, VSM, and VNA. The study shows that increasing the Sn-substitution leads to weakening the interaction between the magnetic sublattices. So, in general, the saturation magnetization (M s) decreases. Low saturation magnetization at high coercivity values gives a high anisotropy field, which provides significant absorption and matching impedance. The sample with substitution of x = 1.2 is the most absorbing sample (more than 99.99% of the incident energy absorbed for 10 mm thickness). The investigated samples have the potential to be useful absorption materials for shielding production (materials that absorb electromagnetic radiation) [ABSTRACT FROM AUTHOR]

• Functional three-components composites were produced. • As components were used hexaferrite and exfoliated graphite dispersed in PVDF. • Strong correlation between composition, magnetic and MW properties was observed. • Anomalous enhancement the composite conductivity and absorption properties was detected. • Total shielding efficiency>|-50| dB was achieved. [Display omitted] RAM (Radar absorbing materials) is strategically important to prevent the targets from being identified. A necessary condition for the absorption of most of the incoming radiation, depending on a combination of conductivity, permittivity, and permeability of the composite's different components, is wave impedances balanced at an air/shield interface. The paper presents a novel RAM developed with the use of exfoliated graphite (EG) for the preparation of composite samples in polyvinyl fluoride (PVDF) in the presence of magnetic inclusion of hexaferrite (HF). The prepared samples were characterized by X-ray diffraction (XRD) and Raman spectroscopy. The morphology was studied by using scanning electron microscopy (SEM). The magnetic properties of all the samples were analyzed by using a vibrating sample magnetometer (VSM). The composites were tested for RAM properties using a vector network analyzer (VNA) in the range of 0.7–7 GHz. The study shows the optimum weight percentage of HF, PVDF, and EG for obtaining high RAM. Inside the prepared composites, EG acts as a conductive path, increasing dielectric and magnetic losses, both of which are critical for trapping incoming electromagnetic radiations and improving total electromagnetic shielding by absorption. In maintaining conductive trajectories in electromagnetic radiation absorption, EG has a significant role in raising the overall shielding efficiency (performance) by more than 50 dB, indicating that the prepared composites in this study can absorb 99.9% of the incoming electromagnetic radiation. The studied composites can be promising absorption blocks in electromagnetic interference (EMI) shielding applications. [ABSTRACT FROM AUTHOR]

• The range of solid solutions of Ti-doped Ba-hexaferrites was expanded to 2.00. • Ti-doped Ba-hexaferrites BaFe 12−x Ti x O 19 magnetic state interpretation was given. • Mechanism of occupation nonequivalent crystallographic positions by Ti was determined. • The spin-glass component of the magnetic phase state is fixed. • The critical magnetic field of the spin-glass component disappearance was found. ga1 A number of solid solutions based on BaFe 12−x Ti x O 19 M-type barium hexaferrite doped with titanium cations up to x = 2.00 were obtained using conventional ceramic technology. The phase composition, crystal structure and unit cell parameters were refined by the Rietveld method using powder X-ray diffraction data up to T = 900 K. It was found that all the compositions have a magnetoplumbite structure satisfactorily described by P6 3 /mmc space group (No. 194). With increasing temperature and doping concentration, the unit cell parameters increase almost monotonically. The minimum volume of V ~ 696.72 Å3 was determined for the composition with x = 1.00 at T = 100 K, while the maximum value of V ~ 714.00 Å3 is observed for the composition with x = 2.00 at T = 900 K. The mechanism of occupation nonequivalent crystallographic positions with titanium cations is established. The spin-glass component of the magnetic phase state is fixed. The T dif temperature of the difference between the ZFC-FC curves decreases with an increase in the concentration of titanium cations and the magnetic field from ~237.2 K to ~ 44.5 K, while the T inf inflection temperature of the ZFC curve increases from ~21.0 K to ~23.8 K. With an increase in the doping concentration, both the D av average and D max maximum clusters grow up to ~ 100 nm. As the magnetic field increases above the critical value, the spin-glass component disappears. For compositions with x > 1.00, the magnetization is not saturated in fields up to 6 T. Along with the formation of the spin-glass component, doping with titanium cations for barium hexaferrite lowers the T C Curie temperature down to T ~600 K. The M s spontaneous and M r remanent magnetizations, as well as the B c coercivity, decrease with increasing doping concentration almost monotonically, while the latter has an inflection point at x = 1.00. The minimum values of spontaneous and remanent magnetization, as well as coercivity, are observed for the composition with x = 2.00 and amount to M s ~17.7 emu/g, M r ~1.9 emu/g, and B c ~3.9 × 10−3 T, respectively. An interpretation of the magnetic state of the doped BaFe 12−x Ti x O 19 barium hexaferrite is given taking into account the mechanism of occupation nonequivalent crystallographic positions with titanium cations. [ABSTRACT FROM AUTHOR]

Multilayer CoFeP/Cu spin-valve nanowires with period of four {FM s /Cu/FM h /Cu} n and five {FM s /Cu/FM s /FM h /Cu} n layers were synthesized by the electrodeposition in the pores of polycarbonate membranes from single electrolyte where FM s are magnetically soft and FM h are magnetically hard layers. The results of magnetic measurements showed that the field dependence of the magnetoresistance of nanowires obtained in the work are typical for multilayer structures with a giant magnetoresistance, the maximum of which reaches ∼9%. Multilayered nanowires based on the giant magnetoresistive effect are interesting objects from fundamental point of view as model objects for explanation of the nature of magnetic ordering in strongly coupled bias magnetic multilayers. These materials are promising for practical applications as sensitive elements in magnetic field sensors, biomedical applications and functional spintronic materials. • First time multilayer CoFeP/Cu nanowires were synthesized from combined electrolyte. • Nanowires were characterized by the sharp soft/hard layers interfaces. • Maximal value of the GMR at room temperature was ∼9%. • Anisotropic magnetoresistance contribution due to spin-orbit interaction was estimated. [ABSTRACT FROM AUTHOR]

Fe 20 Ni 80 alloy nanotubes with different lengths of 3 μm, 6 μm, 9 μm, 12 μm and with "caps" were formed using template synthesis in the pores of PET membranes. The "caps" begin to form over individual nanostructures due to uneven growth, when some tubes reach the template surface before the others at the end of active growth stage. The influence of growth mechanism at different formation stages on the nanotube structure and morphology as well as the correlation between their structural properties and magnetic behavior of arrays were comprehensively studied. The structural parameters (crystallinity degree, lattice parameter and microstresses) were demonstrated as a dependence on the nanotubes length. The structural and magnetic correlations with the processes taking place at various stages of nanotubes evolving from nucleation to active growth and to "caps" formation were analyzed. With increasing the nanotube length, the magnetization reversals in parallel and perpendicular magnetic field directions substantially differ which is explained by the formation of easy anisotropy direction of a helical type. The considerable contribution of "caps" to the magnetic properties of nanotubes was demonstrated for the first time. • Fe 20 Ni 80 alloy NTs with different lengths were formed by template synthesis method. • Structural changes in relation to the NTs growth mechanism were analyzed. • Correlation between structural and magnetic properties of FeNi NTs was defined. • Influence of the "caps" formed at the upper part of NTs was discussed. [ABSTRACT FROM AUTHOR]