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This study investigates the effects of Zn substitution on the magnetic properties of ∼5 nm cobalt ferrite nanoparticles (ZnxCo1−xFe2O4, where x = 0, 0.13, 0.34, and 0.55), demonstrating that Zn substitution induces complex changes in spin canting and prompts a redistribution of cations among the sublattices. We reconstructed the magnetic structure of these spinel ferrites by integrating the classical two-sublattice Néel model of ferrimagnetism with the data obtained from 57Fe Mössbauer spectrometry. Consequently, this research provides a comprehensive understanding of how Zn substitution tunes the magnetic properties of CoFe2O4 nanoparticles, offering valuable insights into the development of magnetic materials with tailored properties for various applications. [ABSTRACT FROM AUTHOR]

Mass transport in bulk spinel ferrites NiFe2O4 is studied computationally using the kinetic activation–relaxation technique (k-ART), an off-lattice kinetic Monte Carlo algorithm. Diffusion mechanisms—difficult to observe with molecular dynamics—are described by k-ART. Point defects are assumed to be responsible for ionic diffusion; thus, both cation and anion defects are investigated. This work focuses on vacancies and interstitials by comparing their properties with two Buckingham potential parameterizations: one with nominal charges and the other with partial charges. Both potentials are corrected at short distances, thus allowing interstitial diffusion and avoiding the catastrophic infinite energies appearing with Buckingham at short distances. The energy landscape along different pathways is described in detail. Both potentials predict the same mechanisms but different migration energies. Mechanisms by which a normal spinel is transformed to an inverse spinel via cation diffusion are unveiled, and diffusion coefficients are predicted. We find that interstitial Ni diffusion involves the movement of two Ni ions and that O interstitials trigger a collective diffusion of O ions, while an O vacancy diffuses by an O ion moving to the center of a cuboctahedron. [ABSTRACT FROM AUTHOR]

One of the main challenges in operating multistate manufacturing systems (MMSs) is maintaining stable and robust production against various disruptions. Therefore, an urgent need exists for an operation and maintenance (O&M) method that optimises MMS resilience, i.e. the capability of withstanding or recover from disruptions of various sources. Consequently, this study proposes an integrated resilience-oriented production and maintenance scheduling approach for MMSs. This approach enhances MMS resilience by reinforcing its adaptivity to the variation in production requirements. Based on a conceptual investigation of operational uncertainty and its mechanism of disruption, this study devotes to (i) formulating a performance loss-based resilience measurement with consideration of operational uncertainties and (ii) proposing a reinforcement learning-based approach to schedule MMS operation and maintenance activities for MMS components of different performance states. An industrial case study of a ferrite phase shifter manufacturing system is subsequently conducted to validate the proposed approach. Results demonstrate the effectiveness of the proposed approach in the resilience optimisation of MMSs. [ABSTRACT FROM AUTHOR]

The mixed zinc-ferrite spinel magnetic nanoparticles (MNPs) with the general formula ZnxFe3−xO4 are among the most extensively studied families of Fe oxides due to their interesting and diverse chemical, electronic, and magnetic properties. These systems offer the possibility of surface functionalization and possess high biocompatibility, making them highly attractive for applications in biomedicine, such as magnetic fluid hyperthermia (MFH). The efficiency of the MFH process relies on the magnetic, structural and morphological properties of the MNPs. The substitution with the Zn ion and the cationic distribution, as well as the synthesis process employed, have a direct impact on the final properties of these oxides. Therefore, it is essential to have tools that enable a comprehensive characterization of the system to assess its performance in MFH. In this study, we have synthesized four ZnxFe3−xO4 MNP systems using three different methods: two by thermal decomposition at high temperatures, one by co-precipitation, and another by co-precipitation followed by ball milling. We analyze the effect of these various synthesis processes on the magnetic and crystallographic properties, aiming to correlate them with the response of each system in MFH. Neutron diffraction data are employed to determine the cation site occupation and to investigate the correlation with the synthesis method. MFH measurements were conducted in media of diverse viscosities, revealing different values of specific loss power, thus demonstrating a clear dependence on the synthesis process and Zn content. [ABSTRACT FROM AUTHOR]

In this paper, the effects of hydrostatic stress on the magnetic properties of Mn-Zn power ferrites are discussed. Ring cores were embedded in cement and the curing process gradually exerted pressure on the core. A novel testing method was developed to continuously measure the power losses and the magnetic susceptibility in dependence on magnetic excitation at a fixed frequency and room temperature with a vector network analyzer. After 450 h, a maximum compressive stress of 120 MPa was reached. Power loss up to 300% was observed, while magnetic susceptibility dropped by 35%. The magneto-mechanical effect on core losses was simulated with the Hodgdon–Esguerra hysteresis model, showing excellent agreement with tested results, which allows us to predict the behavior of ferrite tiles embedded in load-bearing surfaces for wireless power transfer (WPT) applications. [ABSTRACT FROM AUTHOR]

The complex permeability and power losses are very important parameters for soft magnetic materials. In this paper, the temperature dependence of these two parameters is investigated for Mn–Zn ferrite. The Hopkinson peak was observed at 440 K below the Curie temperature (TC), and the domain-wall resonance peaks and the natural resonance peaks gradually move to lower frequencies until the Hopkinson temperature (TH). Further, the domain-wall resonance peaks from relaxation type to resonance type are observed by fitting the permeability spectrum, which is related to the reduction of the loss factor. In addition, the power losses were measured from 245 to 365 K and divided into hysteresis loss (Ph), eddy current loss (Pe), and excess loss (Pexc). Each loss contribution was discussed to be dependent on temperature. The results show that at high temperatures and high frequencies, the thermal superposition effect will cause an abnormal increase in excess loss. [ABSTRACT FROM AUTHOR]

The solid-state synthesized dense ceramic composite, consisting of M-type hexaferrite Ba 0.5 Sr 0.5 Fe 12 O 19 and inverse spinel ferrite Ni 0.3 Co 0.2 Zn 0.5 Fe 2 O 4 (NCZFO) with varying concentrations, demonstrates the presence of apparent colossal permittivity along with dielectric relaxation behaviors at the higher frequency regions for all the composites. This phenomenon manifests as a giant dielectric permittivity of approximately 10 5 at 1 kHz, gradually decreasing to around 10 3 at 1 MHz at room temperature. It can be attributed to the Maxwell–Wagner interfacial polarization, which arises from the presence of different conductivity regions within the microstructures of the composite. The dielectric permittivity and the activation energy are also increased with higher NCZFO content, indicating an intricate microstructure influencing the electrical response by impacting charge carrier movement and ion migration. The presence of both Fe and Co cation defects and oxygen vacancies enhanced non-uniformity in the microstructure with different conductivity regions. The appearance of relaxation peaks in the higher frequency region can be attributed to inhomogeneity in the microstructure. In conjunction with the equivalent circuit analysis, the Nyquist plot confirmed that the electrical response at a lower frequency primarily arises from grain boundaries. The departure from ideal Debye-type relaxation behavior in the electrical response is also confirmed by impedance analysis. Furthermore, the step-like increase in AC conductivity with frequency suggests that the electrical response observed at a lower frequency is not intrinsic. Rather, it indicates the depletion of insulating grain boundaries due to diffusive ion motions resulting from defects. This observation reinforces that the high dielectric permittivity observed in the composite is not an inherent characteristic of the constituent materials. Instead, it arises from the microstructure and the influence of defects within the material. [ABSTRACT FROM AUTHOR]

The cellulose fibers that form washi are longer than those of regular paper made from wood pulp. Hence, the mechanical properties of washi can be higher than those of conventional paper. This study evaluated the magnetic, magnetostrictive, and tensile properties of negative magnetostrictive cobalt ferrite (CoFe2O4) particle dispersed handmade washi (washi−CoFe2O4). The CoFe2O4 additives magnetized the washi, which displayed negative magnetostriction with the fiber direction perpendicular to the magnetic field and in the parallel fiber direction. Concerning the mechanical properties, the washi−CoFe2O4 displayed an elongation of up to 77% after yielding. [ABSTRACT FROM AUTHOR]

A temperature factor is one of the main parameters in the synthesis of nanoparticles and can affect considerably the arrangement of atoms in the lattice. In the system of magnetically hard CoFe2O4 spinel ferrite, the distribution of cations directly determines the magnetic properties of the sample. It was studied, on products of co-precipitation synthesis followed by a temperature dependent sinterization, by x-ray diffraction (XRD), x-ray absorption (XAS) using synchrotron radiation, vibrating sample magnetometry, and 57Fe Mössbauer spectroscopy (MS). From the Rietveld refinement of XRD patterns, the site occupancies reveal the following trend: with a decrease in the sintering temperature, the inversion degree parameter γ, which is a fraction of Co ions residing in the octahedral sites, decreases. For the highest sintering temperature explored in this work, 1000 °C, γ ≈ 0.83 giving rise to (Co0.17Fe0.83)A[Co0.83Fe1.27]BO4 formulation. For the lowest sintering temperature explored, 500 °C, the inversion degree is approximately 0.69 giving rise to (Co0.31Fe0.69)A[Co0.69Fe1.31]BO4 formulation. The propensity for the cationic arrangement was also confirmed by MS. Qualitative analysis of XAS at Co L3,2 edges strongly supports the tendency observed by XRD: the lower the sintering temperature, the more Co ions tend to occupy the tetrahedral sites. The magnetic behavior of the samples is consistent with the particle size which was determined by transmission/scanning electron microscopies. The particle size is the product of different sintering temperatures after the primary synthesis. [ABSTRACT FROM AUTHOR]

Comparison of magnetoelectric properties of two-layer heterogeneous systems based on Mn0.4Zn0.6Fe2O4 ferrite and PbZr0.53Ti0.47O3 piezoelectric ceramics with ratio of the piezoelectric coefficient to the permittivity pd31/pɛ33 = 0.06 and two-layer heterogeneous systems based on Mn0.4Zn0.6Fe2O4 ferrite and PbZr0.53Ti0.47O3/epoxy piezoelectric composite with pd31/pɛ33 = 0.07 − 0.09 was carried out. It was revealed that the magnetoelectric properties of the heterogeneous systems enhance with an increase in pd31/pɛ33 for a piezoelectric. [ABSTRACT FROM AUTHOR]

This study reports new observations from the fabrication of high-aspect-ratio hollow tubes of SS410 through wire-arc directed energy deposition (wire-arc DED) process. Characterisation work was performed on a single tube as a function of its build height. The maximum ultimate tensile strength (UTS) of 1372 MPa and maximum yield strength (YS) of 980 MPa were achieved in the middle region of the tube. The highest UTS in the middle was attributed to the low delta ferrite content. The reduction of delta ferrite was found to be linked with the repetitive heating and cooling. In contrast, the top and bottom sections exhibit a substantial presence of delta ferrite, indicating that the cyclic effects were not considerable. Nevertheless, the presence of significant ductility in the bottom region of the component indicated the occurrence of tempering effects. This observation is further supported by the lower levels of local strain observed using KAM mapping. Overall, this work proposes a novel fabrication method for producing hollow sections with superior strength and ductile properties. [ABSTRACT FROM AUTHOR]

To fulfill the urgent demand for materials suitable for contemporary high-frequency applications, Eu-substituted Ni 0.55 Zn 0.35 Co 0.1 Eu x Fe 2- x O 4 (NZCEF, 0 ≤ x ≤ 0.10) composite ferrites were successfully synthesized by a solid-state reaction method, demonstrating characteristics apt for high-frequency functionalities. Detailed examination via SEM and EDS confirmed the compositional purity of these ferrites. Microstructural analysis indicates that the incorporation of europium results in a reduction of the average grain size in NZCEF composites, enhancing the material's densification. Measurements of resistivity and dielectric properties reveal that Eu doping affects the concentration of Fe2+ and Fe3+ ions as well as lattice defects within the ferrite, thereby leading to higher dielectric constants and resistivity (ρ , 6.51 × 108 Ω m). Magnetic analysis confirms that the substitution with Eu ions significantly increases both the coercivity and the ferromagnetic resonance frequency (f r), from 25.7 Oe and 445 MHz to 45.73 Oe and 1.22 GHz, respectively. This improvement is attributed to changes in grain size and domain wall motion. Consequently, Eu3+-substituted NZCEF ferrites exhibit superior electromagnetic properties, making them ideal candidates for advanced high-frequency material applications. [ABSTRACT FROM AUTHOR]

Removing radioactive corrosion products from Cr-containing iron oxides require a multi-step and multi-cycle decontamination process. The present article brings out the effect of divalent metal ion substitution on the release rate of chromium in the oxidative pre-treatment step. The non-stoichiometric cobalt chromium ferrites were synthesized, characterized and effect of Zn2+/Ni2+ substitution on the dissolution behavior was probed. The dissolution rates decreased with increasing the degree of inclusion and showed minima at ~ 0.4–0.6 atom% which is explained on the basis of lattice structure. It is concluded that the dissolution kinetics of native nickel–chromium ferrites in reactors increases with metal ion inclusion. [ABSTRACT FROM AUTHOR]

In this study, Cu-alloyed ductile cast iron treated by different first-step temperatures and times was investigated. The influence of the amount, morphology and distribution of acicular ferrite and retained austenite on the mechanical properties of the two-step austempered ductile iron (ADI) was analyzed. The results indicated that acicular ferrite was both nucleated and grown in two-step austempering. The thinner and sharper acicular ferrite formed at lower temperature at first step austempering was the ferrite needle, the thicker and blunt acicular ferrite formed at higher temperature at second step austempering was ferrite bunch. Ausferrite refinement, austenitic volume fraction and stability were strongly influenced by the phase transformation amount during first step austempering. A low transformation amount at the first- step of austempering process led to a decrease in austenite stability, which resulted in martensite formation and was detrimental to the mechanical properties. The overmuch transformation amount at the first-step of austempering process led to a similar morphologic ausferrite compared to single step ADI treated at the corresponding first-step temperature, which showed minimal improvement in the comprehensive mechanical properties. The maximum ultimate tensile strength, yield strength and elongation reached 1280, 1190 MPa, 10.2% respectively, as the first-step temperature increased to 280 °C due to the ausferrite refinement. The impact energy and fracture toughness maintained an increasing trend and reached a maximum at 93.5 J and 66.72 MPa m1/2, respectively, as the first-step temperature increased to 320 °C. The ultimate tensile strength and yield strength gradually increased with the first-step time increased, while the elongation, impact energy and fracture toughness gradually decreased. Ausferrite refinement was attributed to the appropriate amount of ferrite needles transformed at first step austempering, which was mainly reason for strength improvement. Austenitic volume fraction and stability increasing were the main influence factor for ductility and toughness of two-step Cu-alloyed ADI. The transformation-induced-plasticity (TRIP) effect was only effective as the induced transformation behavior was retarded to yield, which was also depended on austenitic stability. An optimal combination of ausferrite refinement, austenitic volume fraction and austenitic stability could be achieved through the appropriate first step transformation amount, which together influence the mechanical properties of Cu-alloyed ADI. [ABSTRACT FROM AUTHOR]

In this work, a novel Ba(CoTi)M-spinel magnetic composite with excellent microwave dielectric-magnetic properties has been developed through a hybrid ceramic process. It can be found that the spinel magnetic nanocrystals are uniformly dispersed at the Ba(CoTi)M grain boundary, while the formation of this particular micro-concrete structure has a good effect on ceramic densification and the reduction of magnetic-dielectric loss. The composite exhibits stable electromagnetic parameters in the S and C bands, as evidenced by a permittivity of about 8, a permeability value exceeding 2, and a relatively low magnitude of tanδ ε and tanδ µ on the order of 10−2. A magnetodielectric resonant antenna operating at 6.2 GHz with a −10 dB impedance bandwidth of 27.4%, and a low profile of 0.14λ 0 was designed, fabricated, and measured based on the hybrid ferrite. The hybrid ceramic scheme plays a crucial role in designing low-loss magnetic media, possessing significant application value in high-performance microwave antennas. • Ba(CoTi)M-spinel composite is prepared by a hybrid ceramic processing technique. • The dielectric-magnetic properties are effectively improved in S and C band. • The ferrite enables the miniaturization and wideband capabilities of MDRA. [ABSTRACT FROM AUTHOR]

The global water resource shortage has evolved into a pressing concern, necessitating the advancement of effective and environmentally sustainable water treatment techniques. Photocatalysis has surfaced as a hopeful technology for eliminating organic contaminants from wastewater because of its efficiency, cost-effectiveness, and eco-friendliness. Here, CeO 2 microspheres and Ni 0.5 Zn 0.5 Fe 2 O 4 (NiZn-ferrite) nanoparticles were synthesized using the hydrothermal method, followed by the fabrication of ternary hybrid composites CeO 2 /NiZn ferrite/multiwalled carbon nanotubes (MWCNT) via ultrasonic treatment. Various analytical techniques including XRD, FESEM, VSM, PL, BET and UV–Visible spectroscopy were employed to characterize the resulting synthesized samples. The hybrid ternary composites demonstrate remarkable efficiency in degradation of reactive red-35 dye through photocatalysis attributed to enhanced surface area. This efficiency is further enhanced when coupled with ultrasonic treatment, leading to a synergistic effect. The catalysts can be easily separated from the suspension due to their magnetic behaviour and thus hold great potential for utilizations in the field of wastewater treatment and environmental remediation. [ABSTRACT FROM AUTHOR]

LiZnTi ferrites with dense microstructure and excellent gyromagnetic properties are a critical class of materials for microwave ferrite devices. Many reported studies have demonstrated that grain refinement and good gyromagnetic properties is often contradictory. In this work, we have successfully prepared a highly-dense LiZnTi ferrite with small average grain size (<1.0μm) and good gyromagnetic properties by hot-pressure sintering (HPS) method. Interestingly, SEM images revealed that the hot-pressure sintering with zero holding time not only promoted densification of the LiZnTi ferrites, but also can realize their grain refinement, which effectively reduced porosity and improved gyromagnetic properties. Meanwhile, we found that the average grains size (GS ave.) of the HPS950 sample is smaller than the TS950 and HPS900 samples due to the synergistic effect of applied pressure (zero holding time) and Bi 2 O 3 liquid phase. Finally, a LiZnTi ferrite with uniform, dense grains (GS ave. = 0.85 μm and ρ r = 98.1 %) and good gyromagnetic properties (4π M s = 3859.6Gs and ΔH = 287.4 Oe) was obtained by hot-pressure sintering at ∼950 °C. [ABSTRACT FROM AUTHOR]

By adjusting the parameters in the additive manufacturing process, the optimization of the microstructure and mechanical properties of 2205 duplex stainless steel (DSS) is of great significance to ensure the reliability of the material in harsh environments. The 2205 DSS samples are prepared by cold metal transfer conditions of interlayer cooling time of 0, 30, 60, and 120 s, respectively, and the microstructure and properties of the samples are characterized in detail. With the increase of cooling time, the height of the samples increases, and the width decreases, and no defects are found in all the samples. It also reduces the grain size and contributes to the uniform distribution of grains. With the extension of cooling time, the proportion of austenitic phase gradually increases from 41.60% to 47.36%, while the proportion of ferrite decreases correspondingly. The mechanical properties of the samples are tested. With the increase of cooling time, the hardness of the samples increases from 646.32(±1.46) to 679.36(±7.27) MPa, and the ductility decreases from 60.10(±0.50)% to 43.67(±2.10)%. The results show that the interlayer cooling time can be used to regulate the formation, microstructure, and properties of DSS. [ABSTRACT FROM AUTHOR]

Effects of the cerium content on inclusions, microstructure, and performance of an Al‐killed low‐sulfur steel are studied. As the cerium content in the steel increases from 0 to 190 ppm, the evolution path of the inclusion composition is Al2O3→CeAlO3→Ce2O2S + Ce2O3, and the inclusion size first decreases and then increases. When the cerium content is 76 ppm, the inclusion size reaches the minimum value. The addition of the ferrocerium is beneficial to the grain refinement of the Al‐killed low‐sulfur steel due to the low disregistry between inclusions and the steel matrix. The grain size of the steel decreases first, and it changes little after the cerium content reaching 76 ppm. The grain refinement is beneficial to increase steel properties. However, excessive inclusions in steel with a high cerium content reduce the tensile strength and the plasticity of the Al‐killed low‐sulfur steel. [ABSTRACT FROM AUTHOR]

This work investigates the role of stable (sing-phased) and unstable (bi-phased) lattice structures in controlling the magnetic spin order and electronic properties in Co-rich ferrites of compositions Co1.25Fe1.75O4 and Co2.25Fe0.75O4. The material was synthesized via the chemical reaction of metal (Co and Fe) nitrates in an alkaline medium and post-heat treatment. The XRD patterns of Co1.25Fe1.75O4 showed a single-phased structure upon heat treatment in the temperature range of 200–900 °C, whereas Co2.25Fe0.75O4 showed a single-phased structure at 900 °C and bi-phased structure at a low heating temperature range of 200–800 °C. The thermally induced irreversibility (non-equilibrium) effect was observed in the lattice structure, magnetic spin order and electrical conductivity. The lattice structure at the (local) microscopic scale showed a more or less metastable state and coexistence of mixed-charge states of Co and Fe ions, irrespective of the single or bi-phased structure. The magnetic and electronic responses are found to be sensitive enough to detect local level non-equilibrium (metastable) states in non-equilibrium and equilibrium crystalline phases seen from XRD patterns. [ABSTRACT FROM AUTHOR]

ABSTRACT Low‐power magnetic coupling resonant wireless power transfer (MCRWPT) systems are less efficient at long transmission distances due to magnetic leakage and losses. For this reason, combining ferrite‐nanocrystalline hybrid shielding and a relay coil, an improved MCRWPT system based on the LCC‐LCC compensation network is designed in this paper. Firstly, the transmission performance of the MCRWPT systems with S‐S and LCC‐LCC compensation networks are compared and analyzed. Secondly, the transfer efficiencies of the MCRWPT system are analyzed when the relay coil is added at different locations, and the transfer efficiencies of the system with single material shielding are compared. Finally, the transmission performance of the MCRWPT system with ferrite‐nanocrystalline hybrid shieling is analyzed using simulation and experiment. Experimental results show that the transfer efficiency of the low‐power MCRWPT system using relay coil and hybrid shielding increases from 40.38% to 69.17% when the input voltage is 40 V and the transmission distance is 250 mm. Compared with the MCRWPT system based on ferrite full shielding, the weight of the MCRWPT system has been reduced by 63.11%. The hybrid shielding method not only improves the transfer efficiency of the MCRWPT system and reduces its spatial magnetic leakage but also has certain cost advantages. [ABSTRACT FROM AUTHOR]

In this study, a novel NiCuZn (Ni 0.24 Cu 0.21 Zn 0.55 Bi x Fe 2- x O 4 (x = 0,0.025, 0.050, 0.075)) ferrite composition (Ni/Zn molar ratio is 24/55) was successfully prepared by the addition of Bi3+ ion for substitution. It is demonstrated that Bi 2 O 3 served as an effective doping agent to reduce the sintering temperature to 900 °C and enhanced the high-frequency magneto-dielectric properties. Notably, the maximum permeability is ∼118 (@ 13.56 MHz) when x = 0.050 with a cut-off frequency of 47 MHz, which is nearly four times higher than that of the unsubstituted sample. In addition, an NFC antenna employing optimized ferrite as an electromagnetic shield sheet was designed and simulated. The results indicated that the chaotic and weakened magnetic field was recovered, and the biased resonant frequency was restored from 31.87 MHz to 13.68 MHz. These findings hold significant scientific importance and practical value in achieving superior electromagnetic shielding performance and miniaturization in NFC system. [Display omitted] [ABSTRACT FROM AUTHOR]

With the miniaturization and integration of electronic components, there has been widespread attention on yttrium iron garnet ferrite (YIG) with high saturation magnetization, high dielectric constant, and low ferromagnetic resonance linewidth. In this work, In–Sn–Cu co-doped YIG ferrite with the chemical formula Y 3 Fe 4.8-x Cu 0.1 Sn 0.1 In x O 12 (x = 0.05, 0.10, 0.20, 0.30) was prepared. The properties of the samples, including their microstructure, crystal structure, magnetic attributes, and dielectric properties, were adjusted through the regulation of the indium doping levels. The microscopic and crystal structures confirm the effective doping of ions in YIG, resulting in an expansion of the lattice parameters. Both the saturation magnetization ( M s) and the ferromagnetic resonance linewidth (Δ H ) are influenced by the level of doping. The maximum value of M s is observed at x = 0.10 (30.86 emu/g), whereas the minimum value of Δ H occurs at x = 0.20 (35 Oe). Additionally, increasing doping concentration also leads to an upward trend in both resistivity and dielectric constant, with the lowest dielectric loss occurring at x = 0.15. This study will provide an effective approach for developing high-performance YIG ferrite that meets the requirements of miniaturization and integration. [ABSTRACT FROM AUTHOR]

Magnetic field-assisted method has been proved as an effective method to improve oxygen evolution reaction performance (OER) of water splitting, however, the essential reason for the improvement of OER performance still remains unclear. Herein, Ni 1- x Zn x Fe 2 O 4 ferrites were prepared by the combination of hydrothermal and calcination method, the magnetic properties, oxygen evolution reaction performance and the effect of applied magnetic field on OER performance were studied and discussed according to the magnetic properties and ion site situation. The magnetic field effect depended on the applied magnetic field strength and the magnetic magnetization density of catalysts, it was attributed to changes of electron state and redistribution of ions in the spinel structure. The overpotential decreased by approximately 50 mV and its double layer capacitance increased about 60 % at 125 mT applied magnetic field. The results provided a newness research view for the domain of electrochemistry. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the structural, magnetic, and blood compatibility properties of Sr2+ substituted for Cu2+ in Cu 1−x Sr x Fe 2 O 4 (x = 0.0 to 1 with a 0.25 increment) nanoparticles synthesized via the sol-gel auto-combustion technique. Regardless of the substitution rate, the sol-gel auto-combustion method consistently yields powders with sizes ranging from 20 to 40 nm. The specific surface area of the produced powders is determined as 12 m2/g. X-ray diffraction analysis reveals that CuFe 2 O 4 exhibits a singular phase; however, as the Sr2+ ion substitution increases, the emergence of various secondary phases becomes apparent, with their proportions increasing with the substitution rate. The magnetic characteristics of the synthesized powders exhibit variations in magnetization, correlating with the distribution of cations in the sublattice points. Coercivities are influenced by both anisotropy and secondary phases. Saturation magnetization decreases from 31.3 (CuFe 2 O 4) to 7.6 (SrFe 2 O 4) emu/g with Sr replacement. The lowest observed coercivity is 429.5 Oe in powders prepared with CuFe 2 O 4 composition, while the highest is measured at 583.8 Oe in nanopowders prepared with Cu 0.5 Sr 0.5 Fe 2 O 4 composition. Moreover, blood compatibility experiments indicate significantly low hemolysis ratios for Cu 1−x Sr x Fe 2 O 4 nanoparticles. Additionally, all examined samples exhibit an increase in Soret band intensity compared to the negative control test, suggesting potential biocompatibility. [ABSTRACT FROM AUTHOR]

Crystal structure, microstructure, static and dynamic magnetic properties of Ba 3-x Nd x Co 2 Fe 24 O 41 (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 (Co 2 Z) ferrites for high frequency applications. [Display omitted] [ABSTRACT FROM AUTHOR]

To expand the effective microwave absorption efficiency of barium hexa-ferrite (BaM)/polyaniline (PANI) composites, a technique based on lanthanum (La) doping and surface carboxylation of BaM nano powders is explored to simulate the interfacial polarization between BaM and PANI. La doping of BaM nano powders not only regulates the magnetic properties and microwave response of ferrite itself, it also activates the surfaces of ferrite particles for the deposition polymerization of PANI. Surface carboxylation provides activated sites for PANI on the surfaces of ferrite particles, leading to formation of rod-like PANI. All these together make contributions to enriched reflection loss modes, resulting in the fine microwave absorption properties. With La-doping in BaM is 5 mol% (x = 0.05) and surface carboxylation has been performed, the microwave absorption properties of the synthesized composites were characterized of a high efficiency of − 51 dB and the effective absorption bandwidth of 2.8 GHz at a thickness of 5 mm. This provides an effective method to improve the microwave absorption performance of the conventional absorption medium, barium ferrite. [ABSTRACT FROM AUTHOR]

A series of chromium-substituted cadmium post-spinel ferrites CdCr x Fe 2-x O 4 (x = 0.0, 0.1, 0.3, 0.5) have been synthesized through the sol-gel auto-ignition method. The structural, vibrational, dielectric, magnetic, and microwave absorption properties of β -spinel ferrites through modern techniques which include X-ray diffraction, FTIR Spectroscopy, and Vector network analyzer. X-ray diffraction technique was used for structural investigation which confirmed the monophasic orthorhombic structure of prepared samples and a detailed study revealed that no impurity/additional phases were detected. Crystallite size and strain were extracted via the Williamson-Hall (W–H) method and Size strain plot (SSP). Vibrational spectroscopy (FTIR) successfully verified the spectral qualities of studied ferrites as measured wave number ranges between 400 and 600 cm−1. X-ray photoelectron spectroscopy verified that all metal ions exist and possess the corresponding electronic states. Electrical properties have been investigated at the microwave region (1 MHz – 6 GHz). The conduction mechanism has been studied via Johnscher power law. The Cole-Cole plot of all the samples consisting of two semicircles corresponding to grain and grain boundaries described the increasing conduction phenomena. In the present research, stable dielectric constant, dielectric loss, enhanced magnetic characteristics, and minimum reflection loss (−31.9 dB) make these CdCr x Fe 2-x O 4 nano-crystallites most suitable candidates for highly dense and high-frequency microwave devices for EMI shielding material. [ABSTRACT FROM AUTHOR]

In this paper, the microstructure and mechanical properties of a new type of low Ni duplex stainless steel after resistance spot welding were studied. The welding current has a great influence on the welding performance of resistance spot welding, so it is necessary to clarify the influence law and mechanism of welding current on the welding performance of low Ni duplex stainless steel. The microstructure of the samples under different welding currents was analyzed in detail by EBSD, and the mechanical properties of the treated samples were measured. The results show that the volume fraction of austenite in nugget zone is affected by changing welding current. This is because the higher cooling rate of resistance spot welding inhibits the phase transformation of ferrite to austenite and reduces the volume fraction of austenite, resulting in the imbalance of ferrite and austenite phases. When the welding current is the largest, the cooling rate is the lowest, which corresponds to the highest austenite volume fraction. [ABSTRACT FROM AUTHOR]

In this work, Co0.5Zn0.5LaxFe2-xO4 (0.00 ≤ x ≤ 0.10) spinel ferrites were synthesized using the sol-gel auto-combustion method. X-ray diffraction (XRD) analysis and Rietveld refinement confirmed the presence of a cubic spinel structure. The crystallite size was estimated to be between 17.5 nm and 26.5 nm using Scherrer's method and 31.27 nm-54.52 nm using the Williamson-Hall (W-H) method. Lattice constants determined from XRD and Rietveld refinement ranged from (8.440 to 8.433 Å and 8.442 to 8.431 Å), respectively. Scanning electron microscopy (SEM) revealed a non-uniform distribution of morphology with a decrease in particle size. The bandgap values decreased from 2.0 eV to 1.68 eV with increasing rare earth (La3+) doping concentration. Fourier-transform infrared (FT-IR) spectroscopy confirmed the presence of functional groups and M-O vibrations. The dielectric constant and dielectric loss exhibited similar behavior across all samples. The maximum tan d value obtained at lower frequencies. Regarding magnetic behavior, there was a decrease in magnetization from 55.84 emu/g to 22.08 emu/g and an increase in coercivity from 25.63 Oe to 33.88 Oe with higher doping concentrations. Based on these results, these materials exhibit promising properties for applications in microwave and energy storage devices. [ABSTRACT FROM AUTHOR]

The effect of the cerium addition on the microstructure and properties of the ductile iron is investigated. The ferrocerium is added to obtain ductile iron samples with cerium contents of 10–750 ppm. In the ductile iron with a cerium content of 60 ppm, the amount and the spheroidization rate of graphites are the highest. The tensile strength of the ductile iron is 488 MPa and the elongation rate reaches 20.17%. For the ductile iron with a high toughness demand, it is necessary to add 60 ppm Ce in the ductile iron to increase the number density and spheroidization rate of graphites. The formation of CeS inclusions effectively promotes the heterogeneous nucleation of graphites, increasing the amount of graphites. The stronger carbon diffusion during the eutectic process increases the ferrite formation in the ductile iron, leading to a lower tensile strength and a higher elongation rate. When the cerium content exceeds 460 ppm, the precipitated Ce2C3 significantly reduces the performance of the ductile iron. [ABSTRACT FROM AUTHOR]

The development of multi-functional and highly mixed ionic-electronic conductive perovskite oxide-based electrodes is becoming an established trend for designing and developing SOFC/SOEC reversible cells. Ideally, the same material can be employed at both electrodes provided that structural stability, high conductivity and catalytic activity are preserved in different operational atmospheres. Here, controlled Fe substitution with a small extent (0.5 mol%) of platinum at the B-site of a lanthanum strontium ferrite is proposed as an effective method to enhance the original oxide properties as both air and fuel electrode for solid oxide cells. The effects of low Pt-doping on La 0.6 Sr 0.4 FeO 3-δ structure, morphology and electrocatalytic activity are investigated and discussed. La 0.6 Sr 0.4 Fe 0.995 Pt 0.005 O 3-δ (05P-LSF) is first tested as air electrode, displaying lower area specific resistance as compared to the Pt-free perovskite. 05P-LSF structural stability and conductivity are assessed in 100 % CO 2 and 50 % CO 2 –50 % CO environments. Symmetric devices are then tested as SOECs in 100 % CO 2 , obtaining a current density output of 1.08 A/cm2 at 1.5 V. Electrochemical impedance spectroscopy (EIS) with distribution of relaxation times analysis (DRT) are used to provide insights on the electrode operation. Pt nanoparticle exsolution at the fuel electrode is induced by voltage application. The device stability under applied voltage is assessed for over 120 h. SOFC/SOEC characterization in a 50 % CO 2 /50 % CO mixture at 850 °C is also provided, obtaining a maximum power density of 270 mW/cm2 in SOFC mode, and a current density of 0.91 A/cm2 at 1.5 V in SOEC mode. [ABSTRACT FROM AUTHOR]

The high-temperature oxidation behavior of Cr-Mn-Si alloyed steel by Fe 2 O 3 contained mold flux in high temperatures, and its effect on microstructure evolution were investigated in detail by TEM, EBSD, CLSM, SEM, and XPS. A novel oxidation mechanism was firstly revealed that the Fe 2 O 3 in mold flux melts during high temperatures plays a role of oxidizing alloyed steels by the released free oxygen ions (O2−) from the transformation of Fe 2 O 3 (Fe3+) to FeO (Fe2+). The formed oxidized dots within the oxide layer changed from SiO 2 and MnSiO 3 to MnCr 2 O 4 spinel phases by increasing the content of Fe 2 O 3 in the mold flux. Notably, the amorphous SiO 2 was discovered in the core region of MnSiO 3 phase due to its selective oxidative behavior in high temperatures. This research provides conclusive evidence that the small size MnSiO 3 oxides can be acted as a nucleation core for the refinement of austenite grains through in-situ observation. [ABSTRACT FROM AUTHOR]

Nanocrystalline cobalt ferrites co-substituted with rare earth Ho and Er (CoFe 2-2 x Ho x Er x O 4 , 0 ≤ x ≤ 0.10) have been synthesized via the sol-gel method. X-ray Diffraction (XRD) confirmed the single-phase spinel structure with reduced crystallite sizes (65 nm–12 nm), micro-strain (ε) and increased lattice constant (a) with Ho–Er co-substitution. Rietveld refinement and theoretical computation revealed Ho and Er occupancy at octahedral sites and Fe and Co ions redistribution between the tetrahedral and octahedral sites. Infrared spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray spectroscopy (EDX) and X-ray Photoelectron Spectroscopy (XPS) supported the formation of the desired spinel structure, aggregated spherical morphology, chemical stoichiometry and elemental states. Magnetic measurements showed a systematic decrease in saturation magnetization (M s), magnetocrystalline anisotropy (K 1), coercivity (H c) and Curie temperature (T c) with Ho–Er co-substitution. Electron Spin Resonance (ESR) exhibited asymmetric resonance peaks, reduced resonance field (H r), linewidth (ΔH pp) and deviation in Lande g values. Impedance spectroscopy revealed two conduction mechanisms (holes and electrons) with distinct activation energies (E aI and E aII). Modulus spectrum analysis confirmed the thermally activated sample-electrode effects and the Nyquist plots indicated the dominant contribution of the grain boundary resistance to the conduction process. A notable enhancement in the dielectric constant (ε′) was observed with Ho–Er co-substitution. The ac conductivity (σ ac) followed the Jonscher Power Law (JPL). The temperature-dependent frequency exponent s(T) , suggests the existence of two conduction mechanisms: non-overlapping small polaron tunneling (NSPT) and correlated barrier hopping (CBH). [ABSTRACT FROM AUTHOR]

This study extensively investigates Ni 0.4 Cu 0.2 Zn 0.4 Fe 2-4x Sn 3x O 4 (x ≤ 0.10) nanospinel ferrites, denoted as NCZFe 2-4x Sn 3x O 4 NSFs, focusing on their structural, morphological, electrical, and dielectric characteristics. Utilizing various techniques such as SEM, EDX, TEM, XRD, and impedance analysis, the research confirms the cubic spinel structure and composition of the nanoferrites. The substitution of Sn 4+ ions into Ni 0.4 Cu 0.2 Zn 0.4 Fe 2 O 4 NSFs is explored, with a thorough examination of dielectric and electrical parameters up to 1.0 MHz and temperatures ranging from 20 to 180 °C. Complex impedance spectroscopy is employed to represent these parameters in a logarithmic 3D graph, revealing insights into ac/dc conductivity, activation energies, dissipation factor, dielectric constant, and loss. The study observes adherence to the power-law frequency rule in ac conductivity and highlights the impact of temperature and substitution ratios on grains, grain boundaries, and elemental composition. The investigation suggests a conduction mechanism involving electron and polaron hopping , and ionic contributions. Dielectric parameters show frequency-dependent changes that relate the dielectric constant to space charge polarization, inhomogeneous dielectric structure, impurities, and grains /grain boundaries. Cole-Cole impedance plots display semicircles dependent on substitution ratios and temperature, emphasizing contributions from grains, grain boundaries, and ionic mobilities. The Nyquist plots of Cole-Cole impedance functions further underscore substantial complexity in the conduction mechanism of the substituted NCZFe 2-4x Sn 3x O 4 NSFs. [ABSTRACT FROM AUTHOR]

Present work reports solution combustion synthesis (SCS) of Co0.5Zn0.5Fe2O4 spinel ferrite, its chemical modification with polymethylmethacrylate (PMMA), synthesis of polyaniline (PANI), and electromagnetic interference (EMI) shielding properties of their composites. Both as-prepared and PMMA-modified Co0.5Zn0.5Fe2O4 adopt cubic spinel structure as shown by X-ray diffraction studies. Field emission scanning electron microscopy images show the agglomerated and microporous nature of the ferrites. High resolution transmission electron microscopy image of as-prepared Co0.5Zn0.5Fe2O4 shows lattice fringes related to (311) plane of the spinel structure. X-ray photoelectron spectroscopy studies reveal the presence of Co2+, Zn2+, and Fe3+ in tetrahedral and octahedral coordinations in the ferrite. EMI shielding properties are evaluated for PMMA-modified Co0.5Zn0.5Fe2O4 and PANI composites in different weight ratios. Composites containing PMMA-modified ferrite and PANI with 50:50 and 10:90 weight ratios show the best performance among all the composites in 2−20 GHz frequency range. Optimized PMMA-modified Co0.5Zn0.5Fe2O4 and PANI composite with the ratio of 10:90 shows shielding effectiveness (SE) values of −16.6 to −24.2 dB in 2−20 GHz frequency region. [ABSTRACT FROM AUTHOR]

Phase shifter (PS) is a key component of a phased array antenna (PAA) system, which controls the microwave phase and realizes the antenna beam forming and scanning. A ferrite PS (FPS) is a current-controlled PS that uses the ferrite's gyromagnetic properties to realize phase shifting. It has the advantages of short phase switching time, low microwave loss, and high reliability and, therefore, has been widely used in low-power PAA systems. However, the power handling capability of the traditional Ku-band FPS is only a few kW, prohibiting FPS from being used in high-power microwave (HPM) PAA systems. Spurred by this concern, this paper proposes a new dual-toroid FPS structure with an external magnetic excitation. By optimizing the PS configuration, improving the integration process, and enhancing the performance of ferrite materials, a single FPS in the Ku band has reached the power handling capability of more than 300 kW with an insertion loss of less than −1.2 dB, the phase shift range of 0°–360°, the width less than 11.5 mm, and the ability of a one-dimensional array. The FPS has the potential to be used in the PAA of an HPM system, laying a foundation for the research of the HPM PAA system. [ABSTRACT FROM AUTHOR]

Ferrites and ferrite-based composites are known for their fascinating magnetic properties, varied redox chemistry, good stability, and excellent catalytic properties, all of which make them useful for a growing range of energy-related applications. The present review provides a concise summary of the basic properties of ferrites, an overview of the applicable synthetic methods, and recent advances related to the application of ferrites and ferrite-based composites in photoelectrochemical cells, photocatalytic CO2 reduction, batteries, supercapacitors, and microbial fuel cells. Special emphasis is placed on materials prepared by modern techniques, including microwave-assisted synthesis, ultrasound-assisted and sonochemical methods, synthesis employing metal-organic framework precursors, and electrospinning methods. The effects of intrinsic magnetism and external magnetic fields on the efficiency of ferrites in selected energy applications are also highlighted. The review concludes with a future outlook for the field that proffers solutions to issues currently hindering the effective utilization of ferrites and ferrite-based composites in energy conversion and storage applications. Highlights: Overview of the preparation and electrochemical energy applications of ferrites and ferrite-based composites Recent applications of ferrites in photoelectrochemical cells, photocatalytic CO2 reduction, batteries, supercapacitors, and microbial fuel cells Effect of magnetism and external magnetic fields on the synthesis and electrochemical applications of ferrites [ABSTRACT FROM AUTHOR]

In this study, an effort was made to compare the impact of diverse organic fuels on structural and magnetic properties of the pure rubidium ferrites. A novel solution‐based combustion method was proposed that offered simplicity, cost effectiveness, and scalability. Pure rubidium ferrite (RbFeO2) was prepared by using diverse organic fuels such as urea, ethylene glycol (EG), and oxalyl dihydrazide (ODH) to facilitate exothermic reaction for homogeneous product. It was then characterized by different physico‐chemical techniques like X‐ray diffraction (XRD), transmission electron spectroscopy (TEM), Mössbauer spectroscopy, and vibrating sample magnetometer (VSM). Findings revealed that the choice of fuel significantly influenced the particle size and magnetic properties of the product. X‐ray diffraction patterns showed the formation of homogeneous nano‐powder confirmed by TEM analysis. TEM image analysis revealed that the average particle size of the final product obtained was 18 nm for EG, 80 nm for urea, and 40 nm for ODH, respectively. Saturation magnetization values were comparable to lithium ferrites reported in the literature. Mössbauer studies indicated that sample prepared by using EG has better magnetic properties for the application as soft magnetic devices. [ABSTRACT FROM AUTHOR]

At present, Fe–Mn–Si shape memory alloy with high corrosion resistance has become the focus of attention because of its special requirements in some fields. On the basis of Fe–Mn–Si shape memory alloy, a corrosion‐resistant shape memory alloy was designed by adding Cr and other alloy elements. The microstructure characteristics and phase ratio control mechanism of the annealed alloy and the influence mechanism of the second phase (ferrite) and ratio on the alloy memory effect are emphatically studied. The results show that ferrite and austenite are evenly distributed at low annealing temperature, and there is thermal‐induced ε‐martensite at the same time. Appropriate thermal‐induced ε‐martensite can strengthen the austenite matrix, and the shape recovery rate is high at this time. With the increase of annealing temperature, the volume fraction and grain size of ferrite increase, the volume fraction of thermal‐induced ε‐martensite and austenite decreases, and the shape recovery rate decreases, but it is beneficial to improve the corrosion resistance. [ABSTRACT FROM AUTHOR]

To meet the challenge of varied working temperatures of inductance components in new energy vehicle and 5G communication, the high- T C high-permeability MnZn ferrite with excellent temperature stability was developed by the addition of SnO 2. In this series of samples, initial permeability μ i maintains large values in a wide temperature range. With increasing the SnO 2 content, the temperature of the second permeability peak T sp decreases and meanwhile Curie temperature T C maintains as high as 160 °C. For the best sample with 6000 ppm SnO 2 , μ i at 25 °C is 7244 and exhibits the excellent temperature stability with the low specific temperature coefficient of 0.35 × 10−6 °C−1 between 25 and 130 °C. The addition of SnO 2 generates Fe2+ and adjusts the magneto-crystalline anisotropy constant K 1 = 0 point, which is responsible for the wide-temperature high permeability. The effect of SnO 2 addition on magnetization process has also been clarified. [ABSTRACT FROM AUTHOR]

The permeability of the Fe Soft Magnetic Composite (SMC) materials need further improve to broaden their application prospect. This research work presents a novel high permeability SMC material which has a low core loss (P cv). The Fe particles formed an elongated strip shape structure through the ball milling process, and the high permeability Mn 0.5 Zn 0.5 Fe 2 O 4 ferrite phase was formed around the elongated strip shape Fe particles via a high temperature in-situ reaction process (ZnO + MnO + Fe 2 O 3 –Mn 0.5 Zn 0.5 Fe 2 O 4). While the added high resistive SiO 2 phase aggregated at the long strip shape Fe particle outer surface and effectively increased the resistivity of the SMCs. As the percentage of the Mn 0.5 Zn 0.5 Fe 2 O 4 ferrite coating increase, the permeability of the double layer coated SMCs gradually increased from 38 for the 1 wt% Mn 0.5 Zn 0.5 Fe 2 O 4 coated SMCs to 170 for the 18 wt% Mn 0.5 Zn 0.5 Fe 2 O 4 coated SMCs. The 3 wt% Mn 0.5 Zn 0.5 Fe 2 O 4 coated SMCs has the lowest core loss (P cv) of 86.9 W/kg at 10 mT, 500 kHz. [ABSTRACT FROM AUTHOR]

Spinel ferrites are materials that have technological and industrial applications. In this study Neodymium (Nd3+) substituted Co–Zn spinel ferrites (CZNF) with chemical formula Co0.7Zn0.3NdxFe2−xO4 with the contents of (x = 0.00–0.20 with a 0.05 difference) was synthesized through sol–gel auto combustion method. The structure of the single-phase formations was verified by using X-ray diffraction (XRD). Moreover, in CZNF samples the crystallite size decreased as the Nd3+ concentrations increased, except for the x = 0.15 sample. Moreover, by using XRD and Fourier transform infrared spectroscopy, the Nd3+ substitution into CZNF spinel ferrite was confirmed. Using image-J software for microstructural analysis, it was discovered that adding Nd3+ ions to CZNF caused an increase in particle size from 7 to 35 nm. It was noted that using UV–visible (UV–Vis) spectroscopy the optical energy band gap (Eg) was maximum at x = 0.00 and minimum for x = 0.20 by additions of Nd3+ to the CZNF samples. The AC conductivity and dielectric constant of CZNF improved with the increase of Nd3+. The addition of Neodymium (Nd3+) ion also decreased the dielectric tangent losses in CZNF spinel ferrites. The saturation magnetization and microwave frequency for x = 0.00 were a maximum of 82.22 (emu/g) and 18.14 GHz, and for x = 0.20, they were a minimum of 25.01 emu/g and 5.48 GHz, respectively. They are prospective materials for a variety of applications because of their dielectric and magnetic qualities, including bolometric devices, microwave absorption materials, and microwave frequency operating devices. The graphical abstract presents the synthesis process of pure and modified Co–Zn spinel ferrites by sol–gel auto-combustion technique. The prospective materials for a variety of applications because of their dielectric and magnetic qualities, including bolometric devices, microwave absorption materials, and microwave frequency operating devices. [ABSTRACT FROM AUTHOR]

Ferrites, known for their unique magnetic, structural, and electrical properties, have garnered significant attention across various scientific and industrial domains. This review provides a comprehensive analysis of the effects of zinc doping on three prominent ferrite materials: MnFe2O4, CuFe2O4, and CaFe2O4. Zinc doping, as a strategic method for tailoring these properties, has emerged as a promising avenue for enhancing their functionality and versatility. In the introduction part to the significance of ferrites, their wide-ranging applications are discussed. This review provides a basic overview of the many synthesis methods, such as co-precipitation, sol–gel, hydrothermal, solid-state etc., and a detailed investigating some nano ferrites. It then delves into the distinct characteristics of each ferrite, highlighting their magnetic behaviors, structural features, and electrical properties. The different methods to study the structural, magnetic, and dielectric properties are also discussed. The effects of zinc doping on MnFe2O4, CuFe2O4, and CaFe2O4 ferrites are discussed comprehensively. This study extensively concentrates on recent industrial applications like photoluminescence, biomedical, and sensors using spinel ferrites. [ABSTRACT FROM AUTHOR]

A hydroelectric cell has been coined as an accomplished device keeping the ability to produce current just by adsorbing a few microliters of water. These cells are the new source of generating green energy which involves no evolution of toxic gases like NO2, SO2, CO, etc. Our current research focuses on studying how to increase the maximum output current (I) in the pure cobalt ferrites by doping with rare-earth ion, yttrium. The yttrium-doped cobalt ferrites with composition (CoYxFe2−xO4, x = 0.00, 0.10, and 0.20) have been prepared using a modified sol–gel citrate method. X-ray diffractogram (XRD) confirmed the formation of cubic crystal structures with crystallite size less than 30 nm. Energy dispersive x-ray (EDX) patterns confirmed the presence of elements (Y, Co, Fe, O) in the prepared compositions. The ionic diffusion mechanism confirmed the dissociation of water molecules by the cations present on the surface of the material at room temperature. Vibrating sample magnetometer (VSM) analysis revealed the increase in coercivity values from 948.81 Oe to 2580.09 Oe with the increase in the concentration of yttrium ions in the cobalt ferrite (CFO) lattice. The V–I polarization curves measured the maximum output current and voltage as around 8.6 mA and 1.1 V, respectively, for the 20% yttrium-doped CFO hydroelectric cells (area = 4 cm2). [ABSTRACT FROM AUTHOR]

Magnesium-doped nickel ferrite nanoparticles with the chemical composition (Ni1−xMgxFe2O4, x = 0.00, 0.20, and 0.40) have been prepared by a modified sol–gel citrate method. Structural analysis was carried out through x-ray diffractograms (XRD) and Fourier-transform infrared (FTIR) spectroscopy. The spherical-shaped morphology of the prepared nanoparticles has been confirmed by field-emission scanning electron microscopy (FESEM). The energy dispersive x-ray (EDX) analysis confirmed the presence of elements (Ni, Mg, Fe, and O) in the prepared compositions. The distribution of cations over tetrahedral and octahedral sites has been confirmed by Rietveld refinement using FullProf software. The phenomena of Maxwell–Wagner polarization is exhibited in the dielectric measurements. Cole–Cole plots showed that the net grain (Rg) and grain boundary resistance (Rgb) values are decreasing for the maximum concentration of Mg2+ ions in the nickel ferrites. Almost 96% deductions in the tangent loss values have been observed at high temperatures with the increasing concentration of Mg2+ ions in the nickel ferrites. Fitting of AC conductivity was carried out using the Jonscher Power Law function. The net magnetization saturation values also decreased from 27.7 emu/g to 16.7 emu/g upon the doping of Mg2+ ions in the pure nickel ferrites. These properties are all desired for materials working under high-frequency applications. [ABSTRACT FROM AUTHOR]

The damage to the shear-punched surface layers such as strain-hardening, strain-induced martensite transformation, and micro-void initiation behaviors was evaluated in the third-generation low-carbon advanced ultrahigh-strength TRIP-aided bainitic ferrite (TBF), bainitic ferrite–martensite (TBM), and martensite (TM) steels. In addition, the surface layer damage was related to (1) the mean normal stress generated during shear-punching and (2) microstructural properties such as the matrix structure, retained austenite characteristics, and second-phase properties. The shear-punched surface layer damage was produced under the mean normal stress between zero and negative in all the steels. The TBM and TM steels achieved relatively small surface layer damage. The small surface layer damage resulted in excellent cold stretch-flangeability, with a high crack-propagation/void-connection resistance on hole expansion. [ABSTRACT FROM AUTHOR]

ZnFe2O4 nanomaterials were synthesized using the sol-gel method with different fuels: citric acid, tartaric acid, ascorbic acid and glucose monohydrate. The effects of organic fuel type and calcination temperature on the magnetic properties of zinc ferrite were studied. X-ray diffraction analysis, thermogravimetric analysis, differential scanning calorimetry, and transmission electron microscopy were used to investigate the process of zinc ferrite formation during the calcination of intermediate gel products, as well as to analyze the crystal structure and samples morphology. The formation of hematite and wurtzite secondary phases was confirmed for some materials, and the influence of heat treatment conditions on impurity formation was discussed. The particle size of zinc ferrite was 11–39 nm depending on the calcination temperature and selected fuel. According to data obtained using a vibrating sample magnetometer, the ZnFe2O4 nanoparticles exhibited ferrimagnetic behavior with saturation magnetization values of 1.92–15.61 emu/g. Changing the fuel type and the calcination temperature makes it possible to obtain ZnFe2O4 nanomaterials with specific magnetic properties. Highlight: Nanosized ZnFe2O4 samples were obtained by the sol-gel method using four fuels. The formation of zinc ferrite nanoparticles has been experimentally confirmed The effect of fuel on phase composition of ZnFe2O4 was studied by X-ray diffraction Zinc ferrite nanomaterials exhibit ferrimagnetic behavior at room temperature [ABSTRACT FROM AUTHOR]

In this study, we investigated the effect of grain size of an initial microstructure (pearlite + ferrite) on a resulting microstructure of induction-hardened microalloyed steel 38MnVS6, which is one topical medium carbon vanadium microalloyed non-quenched and tempered steel used in manufacturing crankshafts for high-power engines. The results show that a coarse initial microstructure could contribute to the incomplete transformation of pearlite + ferrite into austenite in reaustenitization transformation by rapid heating, and the undissolved ferrite remains and locates between the neighboring prior austenite grains after the induction-hardening process. As the coarseness level of the initial microstructure increases from 102 μm to 156 μm, the morphology of undissolved ferrite varies as granule, film, semi-network, and network, in sequence. The undissolved ferrite structures have a thickness of 250–500 nm and appear dark under an optical metallographic view field. To achieve better engineering applications, it is not recommended to eliminate the undissolved ferrite by increasing much heating time for samples with coarser initial microstructures. It is better to achieve a fine original microstructure before the induction-hardening process. For example, microalloying addition of vanadium and titanium plays a role of metallurgical grain refinement via intragranular ferrite nucleation on more sites, and the heating temperature and time of the forging process should be strictly controlled to ensure the existence of fine prior austenite grains before subsequent isothermal phase transformation to pearlite + ferrite. [ABSTRACT FROM AUTHOR]