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The structural, magnetic, and dielectric properties of Yb ions substituted Ca-hexaferrites (Ca-HFs) synthesized using the citrate sol–gel method were studied. XRD and SEM, techniques were used to evaluate the size and shape of the samples. X-ray powder diffraction (XRD) patterns of prepared samples revealed the production of a single M-type single phase hexagonal ferrite with space group 167: R-3c, hexagonal of P63/mmc for structural characterization. Using a scanning electron microscope, the surface morphology of the particle was investigated, and the particle size was determined (SEM). FTIR spectra confirmed the iron–oxygen bands of X-type hexagonal ferrites at tetrahedral and octahedral sites. The high influence of Yb+3 substitutions on the FTIR spectra further confirmed that the dopants play a significant role in these ferrites. The electrical and dielectric properties of Yb substituted Ca-HFs were investigated using the complex impedance spectroscopy technique at various temperatures, frequencies, and substitution ratios. Yb substitution was discovered to have a significant impact on dielectric loss, dielectric constant, Ac conductivity, and dissipation factor. It was fascinating to see how Ytterbium replacement resulted in a significant improvement in magnetic characteristics. With a given substitution ratio, activation energy levels can be altered to a certain level. The Verway Hopping Model, Maxwell Wagner Model, and Koop's theory were used to describe the conduction and polarization mechanisms. The trend was also influenced by the substitution of Yb. Eddy current losses, devices like Multi-Layer Chip Inductors (MLCI), and other microwave applications can benefit from the achieved ranges of both features. [ABSTRACT FROM AUTHOR]

The rare earth (Yb3+) substituted W-type hexagonal ferrites with composition CaPb 2-x Yb x Fe 16 O 27 (x = 0.0, 0.5, 1.0, 1.5, 2.0) were synthesized by a facile and cost-effective sol-gel auto combustion method with post heat treatment. The synthesized hexagonal ferrites were characterized by a variety of analytical techniques, and an impedance analyzer was used to investigate the effects of Ytterbium on structural, magnetic, spectral and dielectric properties. The relationship between their impedance, structure and dielectric properties was investigated. The X-ray diffraction patterns verify the presence of single-phase W-type hexagonal ferrites. Physical properties such as D bulk (bulk density), D xrd (X-ray density), and P (porosity) of the CaPb 2-x Yb x Fe 16 O 27 W-type hexagonal ferrites were calculated. The bulk density of all the samples was decreased, and X-ray intensity was increased with the Ytterbium replacement in the W-type hexaferrite. By adding Yb3+ ions, the lattice parameters, cell volume and X-ray density were reduced due to the substitution of ytterbium with smaller ionic radii compared to the lead ion with large ionic radii. The AC-conductivity was increased from (1.523 × 10−5 to 6.699 × 10−5) Ωcm−1. The dielectric constant and tangent loss was found to decrease substantially. The magnetic properties were found to enhance by the substitution of Yb3+. The low coercivity value of Yb3+ substituted W-type hexagonal ferrites are suitable for magnetic recording media operated at a high-frequency regime. The enhancement of electrical, dielectric and magnetic characteristics suggests these materials as promising for multi-layer chip inductors (MLCIs) circuit applications. [ABSTRACT FROM AUTHOR]

A significant structural modification and enhancement of the electrical and magnetic properties with dilute substitution of Zr (≤1mol.%) in the Bi0.8La0.2Fe1-xZrxO3 system has been reported. A mixture of rhombohedral and orthorhombic phases was detected in these conventionally sintered ceramics. Transition from a leaky state to an insulating state was observed upon Zr substitution. This is the first time that a drop in the electrical conductivity as large as 6 orders of magnitude for doping as small as 0.25mol. % in bismuth ferrite systems has been reported. An investigation on the nature of this abrupt transition revealed the dominant role of defects. A proper consideration of possible defect reactions taking place during and after sintering satisfactorily accounts for the observed modulation in the electrical properties. Both AC and DC measurements indicate that, before Zr substitution, ptype hopping conduction prevails with an activation energy as low as ~0.57 eV, whereas the Zr substitution makes oxide ion migration the central mechanism for conduction with the activation energy of ~0.96-1.08 eV. In contrast to that, the magnetic properties of the compounds experience a more subtle effect; a gradual modification of saturation magnetization and coercivity with Zr substitution is observed. Curve fitting of the magnetic hysteresis loops not only allowed extraction of three separate contributions from the magnetic response but also helped to explain the effects of Zr on the magnetic properties. Modifications of structural characteristics and magnetic anisotropy of the samples are believed to be the primary driving force behind the improvement in the magnetic properties. [ABSTRACT FROM AUTHOR]

• The samples Ca 0.5 Ba 0.5-x Cu x Fe 2 O 4 (x = 0.00, 0.125, 0.250, 0.350, 0.500) spinel ferrites prepared by sol–gel auto combustion method results in enhanced structural, dielectric and magnetic properties. • XRD patterns of samples indicate that the peaks match well with the standard patterns of the spinel ferrites. • Crystallite size lies in the range of 37.43–50.07 nm. • At room temperature the conductivity of ferrites is due to impurity, as at higher temperature conductivity is occurring through polaron hopping. • Dielectric constant according to Maxwell–Wagner model the dielectric substance contains with heterogeneous structure thought that good conducting grains separated by highly resistant thin grain boundaries. • Dielectric losses very essential part of the sum core loss in magnetic materials, According to Hudson theory. Copper-substituted spinel ferrites with nominal composition Ca 0.5 Ba 0.5-x Cu x Fe 2 O 4 (x = 0.00, 0.125, 0.250, 0.350, 0.500) were successfully prepared by the sol–gel auto combustion route. The fabricated Nano-ferrites underwent a five-hour annealing process at 800 °C in a furnace. By the X-ray diffraction (XRD) analysis and dielectric measurements, the structural and electrical behavior of Ca 0.5 Ba 0.5-x Cu x Fe 2 O 4 nanoparticles were examined. Formations of a single-phase cubic structure of all prepared samples were estimated by the X-ray diffraction analysis. Crystallite size ranges from 37.43 to 50.07 nm. With the addition of Cu2+ cation, the lattice parameter, dielectric characteristics, and magnetic parameters were enhanced. It was observed that dielectric properties were improved significantly with the doping of copper. The dielectric constant and dielectric loss were found to decrease at high frequencies. On the other hand, an increase in AC conductivity was observed with increasing frequency by Maxwell Wagner and Koop's models. The VSM study confirms the improved magnetic properties of the sample. Remanent magnetization, saturation magnetization, and coercivity were improved significantly with the doping of copper cation. Based on these improved dielectric and magnetic characteristics, the prepared materials are strongly recommended for different electronic components and energy storage devices. [ABSTRACT FROM AUTHOR]

The main theme of this work is to synthesize and investigate different properties of Pr3+‐Cu2+ substituted X‐type hexaferrite Sr2‐xPrxCo2Fe28‐yCuyO46 with concentration (x = 0, 0.02, 0.06, 0.1 and y = 0, 0.1, 0.3, 0.5) by adopting the sol–gel method. The XRD patterns show the single phase for all the samples. The Pr3+‐Cu2+ substitution in pure X‐type hexaferrites changes the structural parameters. The increment in dielectric properties with Pr3+‐Cu2+ substitution is observed and the patterns show anomalous dielectric behavior. The FTIR analysis also confirms the single phase for the prepared materials. The magnetic properties of the material are enhanced with additives. The difference in saturation magnetization, coercivity, and remanence is observed on the basis of allocated cations onto the different lattice sites. The linear increase in saturation magnetization, remanence, and coercivity make them useful as permanent magnets. The thermal analysis is carried out to know the sintering temperature at which the single X‐type phase can be attained. The material exhibits the minimum value of reflection loss (microwave absorption) at higher frequencies that make this material useful to act as microwave absorbing material (MAM) for super high frequency (SHF) devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • M type hexaferrites with composition Pb 1-x Cr x Fe 12 O 19 x = (0.0,0.1,0.2,0.3,0.4,0.5) were synthesized by the sol-gel auto combustion technique. • Peaks of the XRD pattern match well with the standard pattern of P63/mmc group with JCPDS card No (43-0002). • Crystallite size lies in the range of 63–53 nm. Lattice parameters, crystallite size and cell volume was found to decrease with the substitution of Cr3+ content. • Dielectric constant and ac conductivity (σ ac) increases gradually with the increase in Chromium doping. Mofreover, Pb 1-x Cr x Fe 12 O 19 with x = 0.2 have exceptional dielectric properties with significant Q-value (4900). • These samples may suitable for high frequency applications such as phase shifter, modulators and also in longitudinal recording media. Chromium substituted M-type hexagonal ferrites with nominal composition Pb 1-x Cr x Fe 12 O 19 where x= (0.0, 0.1, 0.2, 0.3, 0.4, 0.5) were prepared via sol gel route. Structure of the single phase lead hexaferrite was estimated from X-ray diffraction (XRD) analysis. Scanning electron microscopy (SEM) confirmed the formation of hexagonal platelets with an average grain size in the range of 53–63 nm. Crystallite size, lattice parameters and cell volume was found to decrease with the increase of Chromium concentration. Magneto crystalline anisotropy and saturation magnetization has been explored through the law of approach to the saturation magnetization. Saturation magnetization first increased and then found to be maximum (64 emu/g) at 30% of Cr3+ doped lead hexaferrite and minimum coercivity (6.54 KOe) was perceived for this composition. Dielectric constant, dielectric loss, tangent loss, real and imaginary part of electric modulus, ac conductivity and Q-values of the prepared samples were also explained. With the increase of dopant (Cr3+) concentration, dielectric constant was increased gradually. These characteristics are suitable for various applications such as phase shifter, modulators, stealth technologies and also in Multilayer chip inductor. [ABSTRACT FROM AUTHOR]

Nanocrystalline Mn-Zn ferrite nanopowders (Mn0.5Zn0.5Fe2O4) were synthesized by co-precipitation technique and post-fabrication annealing has been performed at different temperature ranges from 400 to 700 °C for 2 h. The effect of annealing on morphology, crystalline phase formation, cation distribution, lattice constant, particle size, magnetic properties, and optical properties was studied by scanning electron microscopy (SEM), x-ray diffraction (XRD), vibrating sample magnetometer (VSM), and UV-visible spectroscopy (UV-Vis) respectively. The crystallite size increased from 14 to 24 nm with the annealing temperature owing to the grain growth process or more technically we say Ostwald ripening mechanism. The decomposition of ferrites at low-temperature results in the formation of hematite Fe2O3 eventually reduced the magnetic properties of ferrites. The hematite, impurity phase, started to dissolve or converted into the ferrite phase after 600 °C. The sample annealed at 700 °C shows a better crystalline structure, phase formation, and larger magnetization compared to the other ferrite samples. The improved magnetic behavior after heat treatment is due to the better alignment of domains at the cost of the grain growth process. The UV-Vis spectroscopy result revealed the maximum absorbance at 380 nm. [ABSTRACT FROM AUTHOR]

A series of W-type Ba-based Co-W ferrites with composition BaCoxCd2-xFe16O27 (x - 0.0, 0.1, 0.2, 0.3, 0.4 & 0.5) were fabricated by co-precipitation process at sintering 1100 °C for 8 h. In order to investigate structural, optical, electrical and magnetic properties XRD, FTIR, IV and VSM tools were employed to confirm the formation of ferrites phase. Crystallite size was observed in the range of 71.79 - 27.88 nm with the increase of cobalt contents to confirm the formation of W-type phase. FTIR investigated the existence of metal oxide (M - O). Electrical resistivity increased in the range of 0.2315 x 107 - 0.5329 x 107 ohm.cm. Saturation magnetization (Ms) of the synthesized sample were observed in the range (37.36 emu/g to 87.42 emu/g) and remanance (Mr) found (2.21 emu/g to 27.81 emu/g) while coercivity (Hc) observed in the range (42.58 Oe to 346.55 Oe). Explored results revealed that such type of behavior by material is suitable for application of magnetic recording media. [ABSTRACT FROM AUTHOR]

• A series of R-type hexagonal ferrites were prepared by Sol-Gel method. • The XRD analysis showed that the R-type hexagonal structure. • The c/a ratio of these samples falls in the range of R-type hexagonal ferrites. • The dielectric properties changes with the increase of Pr3+ contents. • The peculiar magnetic properties were observed with Pr substitution. A series of rare earth Pr3+ element substituted, Sr 1-x Pr x Mn 2 Fe 4 O 11 (x = 0, 0.02, 0.06, 0.1) R-type hexagonal ferrites has been synthesized by adopting the Sol-gel method. The influence of Pr-substitution on its structural, electrical, dielectric and magnetic behavior was examined. XRD patterns indicate the single phase for all the samples. The lattice parameters and unit cell volume changed with the substitution of Pr3+ contents. The electrical resistivity of the sample significantly varied with the substitution of Pr3+ ions. The sample with the Pr3+ concentration x = 0.1 was observed to have highest resistivity among the others. The dielectric constant was found to decrease at high frequencies for all samples. The tangent loss revealed the hopping type conduction between Fe3+ and Fe2+ sites. The increase in AC conductivity was observed as a function of frequency. The sample with concentration x = 0.1 revealed the maximum value of polarization. A peculiar magnetic trend was observed for all samples upon the substitution of Pr-contents. The unsubstituted sample exhibited the soft ferrimagnetic properties while the paramagnetic behavior was observed for Pr concentration x = 0.02 and last two concentrations (x = 0.06 and 0.1) unveiled the superparamagnetic nature. [ABSTRACT FROM AUTHOR]