Low Magnetic Loss Research Articles

Magnetic and mechanical properties of a sintered Fe-Si alloy with precipitated particles

A sintered Fe-Si alloy with Fe-Ta system particles was fabricated by a synthetic route of sintering via evaporation of an Fe-Si matrix and diffusion of Ta by sintering in high vacuum at high temperature. The Fe-Ta system particles precipitated on the surface and in grain boundaries of the matrix after sintering. The precipitated particles along grain boundaries in particular could contribute to improving mechanical strength by preventing intergranular fracture. The almost full densification observed after sintering and the disordered A2 phase of the matrix could also contribute to improving the strength. The sintered Fe-Si alloy with a controlled Si ratio and precipitation had low magnetic coercivity, low magnetic loss, high magnetic permeability, and high saturation magnetization, but it also maintained high mechanical strength. The fabricated Fe-Si alloy with precipitation showed much better magnetic and mechanical properties than those of conventional sintered alloys and even Si steel sheet (35H300).

Synthesis and characterization of (Ba2Zn2Fe12O22)1−x(NiFe2O4)x ferrite composites for antenna applications

A series of (Ba2Zn2Fe12O22)1−x(NiFe2O4)x ferrites (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) were successfully synthesized by one-pot coprecipitation route. XRD analysis reveals the formation of Ba2Zn2Fe12O22 and NiFe2O4 composite after sintering calcined precursor powder at 1200 °C/4 h. Densification behaviour was evaluated by Archimedes’ principle. Field emission scanning electron microscopy was used to study morphological characteristics. Room temperature magnetization behaviour was evaluated using a vibrating sample magnetometer. In composite, it was observed that the saturation magnetization (Ms) and coercivity (Hc) increased with increasing NiF content. With the increase of NiF in the composite, the permittivity (ε) decreased from 28.6 (for x = 0.2) to 13.6 (for x = 0.8) with the corresponding decrease in dielectric loss (tanδε) at 100 MHz. The permeability (μ) also decreased from 21.3 (x = 0.2) to 17.9 (x = 0.8) with the associated decrease of the magnetic losses (tanδμ) at 100 MHz. Miniaturization factor (n) of 19.2 and characteristic impedance of 1.1 were obtained for x = 0.4 composition at 100 MHz along with low dielectric loss factor (tan δε/ε) and magnetic loss factor (tan δµ/µ). The ferrite resonator antenna was fabricated using FR4 as substrate and ferrite pellet as magneto-dielectric resonator material. The antenna characteristics parameters reflection loss S (1,1) and voltage standing wave ratio (VSWR) were measured by vector network analyser (VNA).

High-performance FeSiAl/(Al2O3-Ni) soft magnetic composites prepared by in situ synthesis method

FeSiAl/(Al2O3-Ni) soft magnetic composites (SMCs) were prepared by sintering FeSiAl/NiO composite powders, and the formation mechanism of the Al2O3-Ni composite coating and performance of the FeSiAl SMCs with different NiO coating content were studied. During sintering, high temperature promoted a reaction between Al and NiO at the FeSiAl/NiO interface, resulting in the in-situ formation of a composite coating comprising Al2O3 coating with high integrity and ferromagnetic Ni coating. The interdiffusion of Al and O2– toward the interface ensured the continuation of the reaction and growth of the composite coating. The composite coating thickened with the increasing NiO coating content, thus showing reduced real part of permeability. Saturation magnetization considerably increased until the NiO coating content exceeded 12.5 wt% owing to residual NiO. Excessive NiO coating content led to the generation of a large amount of Ni, which was not conducive to the integrity of the Al2O3 coating and increased magnetic loss. The FeSiAl SMCs with 5.0 wt% NiO coating content exhibited exceptional performance with high saturation magnetization (135.3 emu/g), good frequency stability of permeability, and low magnetic loss (63.7 W/kg at 0.05 T/20 kHz).

Preparation and Magnetic Properties of Low-Loss Soft Magnetic Composites Using MgO-Phenolic Resin Coating.

Optimizing the interface between a magnetic powder matrix and an oxide-insulating layer is an effective method to improve the permeability and lower eddy current loss of iron-based soft magnetic composites. In this study, in order to improve the bonding strength of the substrate and insulation layer, soft magnetic composites were prepared by pressing and heat treating with reduced iron powder as a magnetic matrix, high-temperature MgO nanoparticles as insulating coating, and phenolic resin as an adhesive. The effects of MgO content on the microstructure and magnetic properties of the composites were investigated. The results of a scanning electron microscopy and an energy-dispersive spectrometer analysis corroborate that the results obtained regarding the frequency characteristics and the resistivity of the iron powder agree with the scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) analysis and confirm their improvement by the presence of an insulating layer of MgO. The resistivity of the sample coated with 4 wt.% MgO is nearly 45 times higher than that of the uncoated sample under the same conditions. The MgO-insulating film formed on the surface of iron powder makes the coated sample have low effective grain size, high resistivity, and low magnetic loss at a high frequency. At 1 kHz, the magnetic loss of the 4 wt.% MgO-coated sample is reduced by 77.3%, and the magnetic loss is only 5.8% compared with the uncoated sample at 50 kHz. This magnetic loss separation study shows that the addition of MgO insulation material can effectively reduce the eddy current loss of the magnetic powder core. The 4 wt.% MgO-coated sample has the lowest hysteresis loss factor and relatively low eddy current loss factor, so it can be determined that the addition of 4 wt.% MgO is the optimum content to attain a low magnetic loss.

High permeability and low loss easy-plane ferrites with multi-ions doped for miniaturized 5G antennas

Ferrites are the desirable candidates for antenna substrates due to their high permeability and low magnetic loss. However, such excellent magnetic properties cannot be maintained in the GHz band due to the Snoek limit. Here, we report a BaCo1.8Zn0.2Fe16O27 (CoZnW) ferrite prepared by doping multiple ions at the lattice (Zn ions) and grain boundaries (Bi/Ca/Si/V ions) of conventional BaCo2Fe16O27 (Co2W) ferrites, achieving a high permeability of 3.3, low magnetic loss tangent of 0.05, and a high figure of merit (FOM=μ′Qf = 66) at 1 GHz, which is much better compared to the previous reports. Moreover, the dimensions of the antenna deploying the multi-ions doped CoZnW are only 52 % of those deploying conventional commercial materials (Fr4) because of its high permeability and low loss. Such a high permeability is attributed to the enhanced saturation magnetization and the reduced anisotropic field achieved by Zn ions modulation. The low magnetic loss is attributed to the reduced damping of domain wall motion and the refined grain size achieved by Bi/Ca/Si/V ions modulation. Our work not only provides a promising candidate for 5G antennas but also uncovers a physical mechanism for the modulation of magnetic properties of ferrites.

Substitution modification mechanism of YIG ferrite with a high spin-wave linewidth via fast relaxation Dy3+ ion doping and sintering modulation

YIG ferrites are often used as nonreciprocal materials in microwave ferrite devices because of their low microwave magnetic and dielectric losses. To comply with the trend of planarization and integration of microwave systems, YIG ferrites are required to withstand higher powers. In this study, we investigated the variation in material microwave properties with material composition and microstructure. The experimental results show that doping the material with high-relaxation ions Dy3+ combined with modulating the sintering holding time can effectively improve the material’s high-power microwave signal withstanding capability, and YIG ferrite with a spin-wave line width of 18.7 Oe is obtained. In addition, when the average grain size of the material is controlled within 5 μm, the effect of the average grain size on the spin-wave linewidth is more noticeable than that of Dy3+ substitution.

Crystal structure, microstructure, and magnetic properties of Ba3-xNdxCo2Fe24O41 hexaferrite ceramics with enhanced magnetic anisotropy

Crystal structure, microstructure, static and dynamic magnetic properties of Ba3-xNdxCo2Fe24O41 (x = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5) ceramics were investigated. Samples were prepared via sintering at 1250 °C for 4 h, and XRD results revealed their crystal structure after Nd substitution. With the increase in Nd3+ ion dopant content, particle porosity increased, leading to slight decrease in volume density. Static magnetic data showed the weak effect of Nd-substitution on saturation magnetization strength and a slight increase in coercivity (from 52 Oe to 75 Oe at x = 0–0.5), while out-of-plane magnetic anisotropy rose significantly (from 10.1 kOe to 14.5 kOe at x = 0–0.5). Dynamic magnetic tests demonstrated noticeable decrease in permeability (from 17 to 8), whereas cutoff frequency increased from 0.8 GHz to 1.9 GHz and the maximum Snoek product reached 18.8 GHz for the sample with x = 0.4. The fitting of real part of permeability using domain wall resonance and natural resonance models revealed that resonance frequency and out-of-plane anisotropy both increased with Nd-substitution. Moreover, despite Nd doping, samples maintained low magnetic loss and high Q value within higher frequency range. Therefore, findings of this study provide a pathway to development of substituted Z-type barium (Co2Z) ferrites for high frequency applications.

0.16BaFeO3-0.84MgFe2O4 hexa-spinel composited ferrites with enhanced magneto-dielectric properties for miniaturized high-frequency antennas

we deeply dived multi-phase-based 0.16BaFeO3-0.84MgFe2O4 ferrite for VHF antennas. The structural and magneto-dielectric properties synthesized at various temperatures (1100 °C, 1125 °C, 1150 °C and 1175 °C) were investigated. The results demonstrated the coexistence of hexagonal and cubic spinel phases. Microstructure analysis indicated higher temperature induced lager grain size and denser structure. Meanwhile, both the saturation magnetization (from 28 to 25 emu/g) and coercivity (19–5 Oe) decreased. In addition, real permeability (μ′) and permittivity (ε′) arose at higher temperature, promising equivalent permeability and permittivity. What's more, relatively low magnetic and dielectric losses (tanδμ ∼10−2 to 10−3 and tanδε ∼10−3 to 10−4) promote low energy loss. Finally, a miniaturized antenna with relative bandwidth of 14.6 %, peak gain of 0.98 dB, and radiation efficiency of 74.6 % was simulated based on the processed ferrites. In conclusion, the presented investigation greatly improves the magneto-dielectric response, which paves the way to realize high performance in VHF antenna application.

The preparation and performances of Co-Zn 18H hexagonal ferrite with an ultra-high magnetic resonance frequency and low-loss characteristics

Modern 5G communication technologies require evolution of antennas towards high frequency and miniaturization. The search for magneto-dielectric materials with simultaneous high permeability, matched dielectric constant, and low loss properties for sub-6 GHz band applications has received considerable attention from both academic and industrial circles. Due to the low magnetic resonance frequency and high magnetic loss, traditional spinel and hexagonal ferrites hardly meet these requirements. In this study, polycrystalline Co-Zn 18H ferrites (Ba5Co2-xZnxTi3Fe12O31) were synthesized by co-precipitation method with only one-step sintering process. The polycrystalline Co-Zn 18H hexagonal ferrite possesses an ultra-high natural resonance frequency (14.5 GHz) and low magnetic loss (tanδμ≤0⊡10), which provides a better performance factor (PF= 68.6 GHz) at a higher operating frequency (4.97 GHz) compared to traditional microwave ferrites. The miniaturization rate of the planar inverted F antenna (PIFA) with Co-Zn 18H ferrite working at 4.0 GHz reaches 13.3 %. These results demonstrate the high potential of Co-Zn 18H ferrites for high frequency and low loss applications.

Soft magnetism enhancement and eddy current suppression in bioinspired Iron‐based nanocrystalline soft magnetic composites with nacre‐like structure

Bioinspired nacre-like structured high-density soft magnetic composites (SMCs) have been successfully constructed using flaky-Fe73.8Si13.5B8.7Cu1Nb3 powders in the supercooled liquid region (SCLR). These densely arranged particles with a consistent planar orientation significantly enhance the soft magnetic properties of SMCs, including high permeability and low magnetic losses. The internal structures of the composites and microstructure evolution of the flaky nanocrystalline particles during the hot-pressing process have been thoroughly studied. Moreover, systematic investigations into the effects of coatings and particle sizes on the maximum permeability and magnetic losses of the composites are conducted. The SMC prepared using the coated particles with a size of 0–100 µm exhibits a high maximum permeability of 2170 (at 1000 Hz) and low magnetic loss of 41.61 W kg–1 (at 1000 Hz and 1.0 T). The losses and permeability analysis reveal that the superior performance of these soft magnetic materials is attributed to their laminated structure, insulation coating, and the reduced planar demagnetizing factor. Compared to the traditional silicon steel, this novel SMCs exhibits high magnetic permeability and reduced magnetic losses at frequencies above 1000 Hz, which possess immense application potential within high-frequency electric machines.

Surface modification of carbon fibers for enhanced electromagnetic absorption

The exceptional chemical and physical properties of carbon fiber make it highly promising for utilization in the field of wave-absorbing materials. However, the low magnetic loss and high complex permittivity of conventional carbon fiber materials limit their use in wave-absorbing materials. Hence, this study presents the synthesis of a FeCoNi/N-doped carbon coating/SCF composite with a distinctive microstructure by an in-situ reduction process. The successful formation of this unique architecture was confirmed through various characterization techniques. The composite material displayed both magnetic and dielectric characteristics. It showed an effective bandwidth spanning 14.77 GHz with a reflection loss (RL) of − 10 dB or less. In addition, it attained the minimum RL value of − 50.5 dB at a distance of 3.5 mm. The composite material is hypothesized to show great potential in electromagnetic wave absorption.

Hexaferrite composites with sintering-induced texture for Snoek's product enhancement and magnetic loss suppression

Hexaferrites with high permeability and low magnetic loss have been attracting great attention from both academic and industrial communities as promising high-frequency materials for modern communication applications. The magnetic properties of hexaferrites are closely related to the crystallographic texture and can be improved by orienting the crystallites. The traditional magnetic field orientation technique, however, has the disadvantages of complicated process and low efficiency. Here, a tunable crystallographic texture of polycrystalline hexaferrite composites achieved by a non-magnetic-field orientation technique is reported. Tabular Co2Z hexaferrite crystallites are synthesized from BaM and Co2Y hexaferrite mixtures and oriented in a form of lamination during the grain growth stage of the sintering process. These layered grains with paralleled easy-magnetization planes play an important role in enhancing the magnetic permeability and suppressing the eddy current from penetrating highly insulating grain boundaries at high frequencies. The textured hexaferrite composite with optimized composition exhibits a high permeability of 16.6, low magnetic specific loss of 0.006, and enhanced Snoek's product of 17.4 GHz at 200 MHz. These results demonstrate an easy and effective method to achieve textured hexaferrite composites without magnetic fields and reveal the potential of hexaferrite composites with sintering-induced texture for high-frequency low-loss magnetic applications.

Enhancing high frequency magneto-dielectric performance with exchange-coupled garnet/spinel ferrite (Y3Fe5O12/Mg0.4Cd0.4Co0.2Fe2O4) composites

Yttrium iron garnet ferrite (YIG), with good magnetic and dielectric properties, was mixed with doped magnesium spinel ferrite (Y3Fe5O12(x)/Mg0.4Cd0.4Co0.2Fe2O4(1-x) (x = 0.3, 0.6, 0.9)) to attain high permittivity and permeability with low magneto-dielectric losses. We have reported the synthesis and enhanced structural, magnetic and magnetodielectric properties of composites for miniaturized antenna applications. The X-ray diffraction (XRD) patterns of all the composites were analysed using the Rietveld method, which confirmed that they exhibited a crystalline structure with a cubic spinel and cubic garnet phase. XRD spectra confirm that the spinel ferrite phase dominates over the garnet ferrite phase in the x = 0.3 composite, whereas it is the opposite for the other composites. In contrast to the parent ferrites, it has been observed that the composites (x = 0.3, 0.6, 0.9) exhibit a higher value of the crystallite size ‘D’ and a lower value of the lattice constant ‘a’. The composite with the x = 0.3 composition has the least porosity and a high relative density. From field emission scanning electron microscopy (FESEM), it has been ascertained that the materials possess a grain size ranging from 0.57 to 0.8μm, with a larger grain size for the x = 0.9 composite, while the x = 0.3 composite has the smallest grain size. Transmission electron microscopy (TEM) scans have corroborated the FESEM micrographs’ findings, indicating that the grains within the composites’ structure exhibit agglomeration. The calculated values of inter-planar spacing of the samples using high-resolution TEM (HR-TEM) matches well with the XRD results. A magnetic study reveals that the composite with x = 0.3 has a good exchange-coupling, the highest coercivity value of 99.2 Oe and a magnetization value of 41 emu/g. The composite with x = 0.3 also has the highest permittivity value of ∼19.5, a permeability value of ∼2.8, but low dielectric and magnetic losses of ∼0.009 and ∼0.002, respectively. These low losses and a high miniaturization factor of ∼7.2 at high frequency (14 GHz) make it a potential candidate for high-speed satellite antenna applications.

Low-temperature-sintering of Co2Z ferrite materials via Dy3+ ion doping for use in high-frequency applications

According to this study, Co2Z ferrite is suitable for applications in high-frequency antennas. Ba3Co2Fe24-xDyxO41 samples with different values of Dy3+ doping concentration (x) in the range of 0.00–0.25 were prepared in the study by employing solid-state sintering and 2.5 wt% Bi2O3 sintering aids. A systematic analysis of the physical phase structure, microstructure, and magnetic dielectric properties of the samples was also performed. The X-ray diffraction patterns of the samples showed that doping with Dy3+ ions and the addition of the Bi2O3 sintering aid had not changed the physical structure of the sample material, indicating that the material was still a Z-type hexagonal ferrite. In addition, according to the magnetic hysteresis loops of the samples, all six groups of them exhibited typical soft magnetic properties. With an increase in the Dy3+ ion doping concentration, the saturation magnetization intensity and coercivity of the samples initially increased and then decreased. The sample with a Dy3+ ion doping concentration of 0.15 had the most uniform grain distribution, largest density, and smallest porosity among the samples. Additionally, that sample had the maximum values of the real parts of the magnetic permeability (7.89) and permittivity (13.90) while having a low magnetic loss (tanδμ≤0.04) and a low dielectric loss (tanδε≤0.03). Thus, this type of magnetic dielectric materials will have significant potential for use in high-frequency antenna applications.

Influence of intermediate annealing temperature on the microstructure and texture of double stage cold rolled non-grain oriented electrical steel

Non-grain oriented electrical steels (NGOES) are commonly used as stacked laminations of rotors and stators in electrical vehicles. In order to achieve the best performance and efficiency for the motor, NGOES need the best possible magnetic properties of high polarization and low magnetic losses. Two important aspects influencing these magnetic properties are the grain size and the crystallographic texture of the material. Grain size and texture of the finished steel strongly depend on the production route and the processing parameters. Another important aspect besides the magnetic properties is the mechanical strength, which is needed to withstand the centrifugal forces, accounted with high rotational speed in high frequency applications. In this work a special processing route for the production of 3.25% Si NGOES sample material has been studied, using laboratory cold rolling and annealing facilities. Compared to the classical processing route of cold rolling and annealing, this alternative method involves two cold rolling steps with an intermediate annealing treatment between the first and second rolling step and a final annealing treatment after the second rolling sequence. The samples were heat treated at different intermediate and final annealing temperatures, influencing the recrystallization and grain growth behavior and thus the resulting microstructure and texture. Finished samples were examined using magnetic testing, tensile testing, light imaging microscopy and by electron backscatter diffraction (EBSD). The results indicate a correlation between the two annealing treatments (intermediate and final) and the final grain size of the steel samples. Furthermore the highly grain size dependent magnetic losses are influenced. EBSD-data was used to interpret the texture and to calculate a parameter describing the magnetic quality of the texture. The results show a strong improvement of magnetically favorable texture components along with increasing intermediate annealing temperatures, enabling significantly better magnetic properties.

Two phase Mg0.7Cd0.3Fe2O4–BaTiO3 composite ceramics with excellent magneto-dielectric properties for antennas in GHz band

Two phase-based composites comprising barium titanate (BaTiO3) and spinel magnesium ferrite (1-x)Mg0.7Cd0.3Fe2O4 +xBaTiO3 (x = 0.00, 0.03, 0.06, 0.09, and 0.12) were investigated. The phase structure revealed the coexistence of the perovskite BaTiO3 and spinel MgFe2O4 phases. The microstructural analysis indicated that the average crystallite size initially increased and then decreased, as the increase in x weakened magnetisation, decreased saturation magnetisation (from 47.5 to 35.9 emu/g) and coercivity (150–0 Oe) were obtained, resulting in reduced permeability at low frequency. The permittivity gradually increased owing to tuning by barium titanate, which has strong dielectric properties, promising a relatively large miniaturisation factor. Further, low magnetic loss (tan δμ ∼10−2) and dielectric loss (tan δε ∼ 10−2 to 10−3) guarantee high quality factor. The low losses and enhanced dielectric properties of the as-synthesised composites could be conducive to improving the behaviour of such magneto-dielectric composite systems in microwave applications.

Simulation of low loss metamaterial based hollow core fiber for guiding mid-infrared (MIR) light

There is a great deal of interest in mid-infrared (MIR) light in diverse fields including spectroscopy, biomedical-applications, medical surgery, and astronomy. Due to higher material absorption, MIR light transmission is generally more difficult than visible light or microwave radiation. Recently, hollow-core MIR fibers are one of the best possibilities among presented several innovations having low Transverse Magnetic (TM) mode losses, although they are many orders of magnitude than Transverse Electric (TE) modes. Studies also have found that metamaterial-based HCF offers excellent potential for transmitting MIR light because of its distinct and flexible optical properties. In this study, a metamaterial-based HCF with an optimized design that uses metal wires with subwavelength spacing embedded in dielectric host, and acts as an effective TM reflector is proposed. In the 3 to 12 μm wavelengths, the effects of the design parameters including shape, number, and spacing of metal wires, dielectric thickness, and the diameter of the core are extensively investigated using finite element method. It is observed that TM01 mode losses are the lowest and a noteworthy confinement loss of 4.69× 10−7 dB/m is found at 9.5 μm wavelength, with an average loss of 5.22× 10−5 dB/m found within the range 8–10 μm wavelength. As the wires are wrapped up in a dielectric, there is a preferred position of 4 μm from the core edge and a number of 40 metal wires that results in the least amount of losses. This analysis could help to design low-loss metamaterial based HCF for guiding MIR light.

The epitaxial iron-yttrium garnet films with homogeneous properties and narrow FMR line width

The growth of iron-yttrium garnet Y3Fe5O12 (YIG) films with of 1...15 μm thicknesses on single-crystal substrates of gallium-gadolinium garnet Gd3Ga5O12 (GGG) was carried out using the method of liquid phase epitaxy (LPE). The influence of the composition and mass of the charge, the temperature regimes, the rates of movement and the substrate rotation on the films parameters were studied. The layered structure caused by the heterogeneity of the chemical composition in the film thickness was determined and studied The dependence of the degree impurity of Pb2+ and Pt4+ ions in YIG films and their influence on the ferromagnetic resonance (FMR) line width ∆H on the films growth conditions was investigated. It’s shown that in order to obtain by the LPE method the series of defect-free films with low magnetic losses and reproducible parameters, it’s necessary to use melt-solutions of large mass (6...12 kg) and apply their additional mixing during the growth process.

High cut-off frequency and low magnetic loss of Bi3+-Cr3+ co-substitution NiCuZn ferrite for chip inductors applications

With the rapid growth of high-frequency chip inductors, there is an urgent demand for NiCuZn ferrite that exhibits low magnetic loss and high cut-off frequency. To enhance its electromagnetic features, this study investigates the doping of Bi3+-Cr3 + ions into NiCuZn ferrite. The research examines the effects of different Cr3+ concentrations on the electric and magnetic properties, as well as the crystal structure of NiCuZn ferrites. The results showed that using a low sintering temperature of 925℃ can obtain NiCuZn ferrite with high population density and uniform microstructure. The inclusion of Cr3+ causes the lattice parameter to decrease, with a preference for octahedral B-sites. Furthermore, the saturation magnetization declines as the concentration of Cr3+ increases, according to the results of the magnetic hysteresis loops. The permittivity measurements demonstrate that the addition of Cr3+ ions can enhance permittivity and reduce dielectric loss. Lastly, NiCuZn ferrite co-doped with 0.30 wt% Bi2O3 and x = 0.15 of Cr3+ ions had appropriate saturation magnetization (∼57.05 emu/g) and coercivity (∼0.680 kA/m), meanwhile exhibited the highest dielectric constant (∼12.32 @ 1 MHz) and cut-off frequency (218 MHz), the lowest permeability loss tangent (0.0036@1 MHz) and imaginary part of the permittivity (0.54@1 MHz), making it a suitable for high-frequency chip inductors.

Effects of ytterbium substitution on the structural, electrical and magnetic properties of Ni–Zn–Co ferrites for microwave equipment

Given the significant impact of microstructure and material composition on material properties, this paper utilizes ytterbium nitrate to enhance the dielectric and magnetic characteristics of NiZnCo ferrite ceramics. In this study, Ni0.5Zn0.4Co0.1Yb0.075Fe1.925O4 ferrites with lower magnetic losses and a substantial cutoff frequency were successfully created using the sol-gel self-propagating method. The study reveals that the adding of ytterbium ions rises the lattice constant from 8.3377 to 8.3586 Å, the porosity from 4.77% to 6.92%, theoretical X-ray density from 5.43 to 5.66 g/cm3, and bulk density from 5.18 g/cm3 to 5.27 g/cm3. The incorporation of ytterbium ions in ferrite decreases the dielectric constant as well as dielectric losses, enhances the DC resistance, and lowers the eddy current loss in the frequency range of 100 Hz to 1 MHz. The addition of ytterbium ions decreases the initial permeability and saturation magnetization of the material while increasing its magnetic quality factor. Additionally, the cut-off frequency shifted to a higher frequency range, from 25.7 MHz to 121.61 MHz, while exhibiting lower losses at higher frequencies. The addition of ytterbium ions has expanded the potential applications of NiZnCo ferrite in high-frequency microwave devices and wireless communications.