Mn-Zn Ferrite Research Articles

Cerium doped superparamagnetic Mn-Zn ferrite as a promising material for self-regulated magnetic hyperthermia

Recently, cubic ferrites (CF) have been widely explored in biomedical applications, especially those that display superparamagnetism behavior due to the desirable absence of remanent field. In this study, we report the self-stabilization of the magnetic fluid hyperthermia (MFH) temperature in the cancer therapy range (42 - 48 ºC) by Ce3+ substitution in superparamagnetic Mn0.8Zn0.2Fe2-xCexO4 ferrite with x = 0.0; 0.015; 0.030; 0.050 and 0.100. A comprehensive characterization was performed in order to investigate the influence of this replacement on the magnetic and structural properties of the ferrite. The samples were synthesized by the sol-gel auto-combustion method and the properties were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), Raman spectroscopy (RS), Mössbauer spectroscopy (MS), vibrational sample magnetometry (VSM), and ferromagnetic resonance (FMR). Magnetic hyperthermia essays were used to obtain the heat induction curves and calculate energy dissipation. We refined the XRD data by the Rietveld method to determine the cation distribution and calculate interionic parameters. Magnetic characterization confirms the superparamagnetic behavior at 300 K, which is expected from the TEM results that show a narrow distribution of particle sizes, with a mean size of about 6.5 nm for all samples. The VSM results show a consistent decrease in magnetization saturation with cerium content that result in a weaker self-heating induction capacity for the cerium-doped samples. FMR results also show a smaller relaxation time T2 for these samples, suggesting a slower energy dissipation rate. These conclusions are confirmed by the heat induction curves and the values of the specific absorption rate (SAR), which are smaller for cerium-doped samples. For the a field with an amplitude of 35.33 kA/m and a frequency of 222 kHz, the temperature of the cerium-doped samples saturates in the optimum interval for cancer treatment, between 42 and 48 ºC. These results suggest that Ce3+ is a promising doping ion to optimize the heating rate behavior of Mn-Zn ferrite for cancer treatment by hyperthermia.

Binder jet 3D printing of Mn–Zn ferrite soft magnet toroidal cores

Traditional powder processing methods for Mn–Zn ferrites limits design freedom and scalability of producing customized soft magnetic cores. In this work, binder jet 3D printing techniques were applied to commercially available Mn–Zn ferrite powders and toroidal cores were successfully fabricated. As-printed Mn–Zn ferrite powders were sintered at different temperatures between 1300 and 1400 °C, resulted in an optimized single-phase spinel at 1350 °C. Microstructural characterization revealed high porosity remained for binder jetted materials and various magnetic property measurements were performed on sintered cores. Despite high porosity, the saturation moments normalized by mass remained similar between binder jetted and traditionally compacted samples. Two-winding method measurements indicated a large demagnetizing field for binder jetted samples. Effective medium theory model was used to estimate the effect of remnant porosity on measured magnetic permeabilities. Importance of novel concepts to successfully realize dense cores through additive manufacturing pathways such as binder jetting is highlighted.

The formation mechanism of MnZn ferrite by the CTAB-assisted synthesis

The formation mechanism of MnZn ferrite by the CTAB-assisted synthesis

Structural and electrical properties of Ni-doped MnZn ferrite synthesized via solid state reaction

Abstract MnZn ferrite is commonly studied due to its exceptional magnetic, electric, and catalytic properties, making it a promising material for hyperthermia applications, magnetic fluid, memory storage devices, drug delivery, virus detection, and photocatalysis. It was identified that divalent nickel cation substitution increases the ferrite conductivity and dielectric constant. This study targets to synthesize Ni-doped MnZn ferrite by a simpler, more convenient, and economic solid state reaction, and to investigate its influence on the structural and electrical properties of MnZn ferrite. Mn0.5-xNixZn0.5Fe2O4 (x=0.1 and 0.2) was synthesized via solid state reaction with calcination and sintering temperature at 1000 °C and 1200 °C, respectively. The structural and electrical properties of the resulting pellet were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The XRD profile, indexed as cubic spinel, indicated good crystallinity and no impurity peaks were detected. As Ni2+ dopant concentration increases, a decrease in lattice parameter and an increase in theoretical and apparent densities were observed. This is attributed to the smaller ionic radius and greater mass of Ni2+ relative to Mn2+. Varying Ni2+ concentration significantly modified the morphology of the ferrite. At higher Ni2+, less uniformity in shape and size was evident in the SEM micrograph since Ni promotes aggregation at the surface. An increase in dielectric constant was also observed with increasing Ni2+ molar concentration. Since Ni2+ presents a high tendency to occupy B sites, its substitution promotes Fe2+ migration to A sites, augmenting Fe2+/Fe3+ hopping resulting in an increase in polarization and dielectric constant.

Optimization of Mn-Zn ferrite doping in phosphate-based glass ceramics for enhanced hyperthermia efficiency and bioactivity

This study investigates the effects of Mn-Zn ferrite (MZF) content and heat treatment temperature on the structural, mechanical, magnetic, and bioactive properties of Na2O-CaO-P2O5 glass ceramics. Various MZF contents (5MZF, 10MZF, 20MZF, and 40MZF) were incorporated into the glass ceramics and subjected to heat treatment at different temperatures (600, 650, 700, and 800 °C). The results demonstrated that increasing the MZF content significantly enhanced the mechanical properties, including Vickers hardness, Knoop hardness, and Young's modulus. For example, the Vickers hardness values increased from 5.6 GPa in 5MZF samples to 7.1 GPa in 40MZF samples. X-ray diffraction analysis revealed the presence of major crystalline phases, such as Ca2P2O7 and Na4Ca(PO3)6, with NaFe3P3O12 and (Zn,Mn)Fe2O4 appearing in samples with higher MZF content. Magnetic measurements indicated that the 40MZF samples treated at 700 °C reached a satisfactory hyperthermia temperature of 43 °C within 16 min. Bioactivity tests showed a decrease in bioactivity with increasing MZF content, whereas cytotoxicity assays confirmed that all MZF-Na2O-CaO-P2O5 bioactive glass ceramics were non-toxic, maintaining over 100 % cell viability after 24 h. These findings suggest that MZF-containing glass ceramics have potential applications in the biomedical field, particularly when enhanced mechanical and magnetic properties are required.

AC Electrical Property and Generation of Extra Eddy Current Loss of Mn-Zn Ferrites at High Frequency

AC Electrical Property and Generation of Extra Eddy Current Loss of Mn-Zn Ferrites at High Frequency

Magnetic and dielectric properties of low‐loss MnZn ferrites with wide temperature stability

AbstractTo meet the needs for higher energy efficiency and a wide operating temperature range of electric vehicles, the low‐loss MnZn ferrites in a wide temperature range have been developed by optimizing the Fe content and the oxygen partial pressure (PO2) during the sintering process in this work. For the optimal sample, power loss at 300 kHz/100mT is 204 kW/m3 at 25°C and remains below 290 kW/m3 in the wide temperature range from ‐10 to 120°C. The loss separation method was employed to clarify the effects of the Fe content and PO2 on power loss. The equivalent circuit model has been employed to fit the complex impedance and it is found that the increase of PO2 enhances both the grain resistance Rg and the grain boundary resistance Rgb. The enhancement of Rgb is mainly responsible for the reduction of eddy current loss and consequently power loss. Dielectric permittivity is as large as about 15000 in this series of samples due to the electric polarization at the rich grain boundaries. Dielectric loss is very low between ‐50 and 150°C and has little contribution to the energy loss.

Evaluation of magnetic hyperthermia, drug delivery and biocompatibility (bone cell adhesion and zebrafish assays) of trace element co-doped hydroxyapatite combined with Mn-Zn ferrite for bone tissue applications.

The treatment and regeneration of bone defects, especially tumor-induced defects, is an issue in clinical practice and remains a major challenge for bone substitute material invention. In this research, a composite material of biomimetic bone-like apatite based on trace element co-doped apatite (Ca10-δ M δ (PO4)5.5(CO3)0.5(OH)2; M = trace elements of Mg, Fe, Zn, Mn, Cu, Ni, Mo, Sr and BO3 3-; THA)-integrated-biocompatible magnetic Mn-Zn ferrite ((Mn, Zn)Fe2O4 nanoparticles, BioMags) called THAiBioMags was prepared via a co-precipitation method. Its characteristics, i.e., physical properties, hyperthermia performance, ion/drug delivery, were investigated in vitro using osteoblasts (bone-forming cells) and in vivo using zebrafish. The synthesized THAiBioMags particles revealed superparamagnetic behaviour at room temperature. Under the influence of an alternating magnetic field, THAiBioMags particles demonstrated a change in temperature, indicating their potential for magnetic hyperthermia, in which THAiBioMags further exhibited a specific absorption rate (SAR) value of 9.44 W g-1 (I = 44 A, H = 6.03 kA m-1 and f = 130 kHz). In addition, the as-prepared particles demonstrated sustained ion/drug (doxorubicin (DOX)) release under physiological pH conditions. Biological assay analysis revealed that THAiBioMags exhibited no toxicity towards osteoblast cells and demonstrated excellent cell adhesion properties. In vivo studies employing an embryonic zebrafish model showed the non-toxic nature of the synthesized THAiBioMags particles, as revealed by evaluation of the survivability, hatching rate, and embryonic morphology. These results could potentially lead to the design and fabrication of magnetic scaffolds to be used in therapeutic treatment and bone regeneration.

Study on liquid-phase sintering and magnetic properties of SLA-printed Mn-Zn ferrite ceramics

To obtain Mn-Zn ferrite magnetic ceramic parts with good densification and magnetic properties, a study was conducted. Mn-Zn ferrite magnetic ceramic parts with a solid particle content of 58 vol% were prepared using stereolithography (SLA). The SLA-cured ceramic blanks were degreased and sintered. The degreasing process for Mn-Zn ferrite parts was optimized using a direct heat degreasing method, resulting in a suitable process for the ferrite magnetic ceramic paste system. The method of liquid phase sintering is proposed for sintering the degreased ferrite parts. The study investigated the impact of the content of accelerant, sintering temperature, and holding time on the density and magnetic properties of Mn-Zn ferrite parts. The optimal parameters were found to be a firing aid content of 3 wt%, a sintering temperature of 900 °C, and a holding time of 90 min. Under these conditions, the parts exhibited a density of 4.43 g/cm3, densification of 91.4 %, saturation magnetization strength of 64 emu/g, and coercivity of 10 Oe. Finally, the sintering control mechanism of SLA-printed ferrite magnetic ceramics was analyzed. The study revealed the grain growth process and magnetization principle of Mn-Zn ferrite during liquid phase sintering. This research provides guidance for the subsequent photocuring printing and degreasing sintering of Mn-Zn ferrite ceramics. Additionally, Mn-Zn ferrite magnetic ceramic parts prepared by the SLA method also hold a wide application prospect in various precision electronic components.

Synthesis, characterization and correlation studies on the Ni–Zn–Mn ferrite as a photocatalyst

Samples of Ni0.3Zn0.7−xMnxFe2O4 (x = 0, 0.15, 0.25, 0.35, 0.45, 0.55) nanoparticles (NPs) were synthesized by auto-combustion flash method. These ferrites were used as catalysts for photodegradation of methylene blue (MB) dye utilizing visible light energy. Structural analysis was carried out using the X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy, while nanoparticle dimensions were elucidated through transmission electron microscopy (TEM). The magnetic and optical behaviours were unveiled via vibrating sample magnetometer and UV–VIS spectroscopy, respectively. The XRD outcomes established the presence of a cubic spinel-type structure for the studied ferrite samples. The FTIR spectra unveiled two absorption characteristic bands of the spinel ferrite. TEM images revealed nanoscale dimensions of ferrite NPs with the range from 21.1 to 51.8 nm. The optical features exhibited an indirect band gap energy spanning from 4.25 to 4.36 eV. Magnetization behaviour displayed a sinusoidal trend corresponding to varying Mn concentrations. The ferrite NPs catalyst (10 mg) yield photodegradation efficiency ranged from 22.8 to 33.9% for 100 ml MB dye solution after 120 min of light irradiation. The effects of dye concentration and catalyst dose on the degradation efficiency were examined using the Ni0.3Zn0.35Mn0.35Fe2O4 catalyst with highest degradation (= 33.9%). On the other hand, the dependence of the degradation efficiency on the structure, morphological, magnetic and optical properties of the photocatalyst was investigated. The findings of this study underscore the potential of the prepared ferrite nanoparticles for advanced applications in environmental restoration.Graphical abstract

Τhe effect of Ni on the magnetic properties of power or high permeability MnZn ferrites

In this article an extensive study is presented on the Ni addition in three subcategories of MnZn ferrites under conditions of constant Mn/Zn ratio and Fe excess, namely i) low frequency (∼100 kHz) power ferrites, ii) medium frequency (∼500 kHz) power ferrites and iii) high permeability (μi ∼ 8000, 25 °C) ferrites. As found, Ni is a useful additive for optimizing the high temperature performance of MnZn ferrites since it increases Curie temperature, saturation flux density, magnetic permeability and decreases power losses at temperatures above 100 °C. In addition, the addition of Ni increases the resonance frequency and the frequency stability of the initial permeability and partly counteracts the ageing effects caused by Co, when it is present in medium frequency ferrites. The magnetic results are explained on the basis of Ni-substitutions on octahedral sites associated with a negative contribution to the total magnetocrystalline anisotropy, thereby shifting the temperature at which the magnetocrystalline anisotropy constant K1 changes sign, to higher temperatures. The morphological results are explained assuming that the presence of Ni is associated with decreased cation vacancy and increased anion vacancy concentrations.

Magnetic loss versus temperature and role of doping in Mn-Zn ferrites

We investigate the effect of different doping schemes on the broadband magnetic losses and their temperature dependence in Mn-Zn ferrites. CaO, Nb2O5, ZrO2, and SiO2 are added with increasing proportions to TiO2-doped prefired powders and, after sintering at either 1275 °C or 1300 °C, the obtained ring samples are tested versus frequency f (DC-1 GHz) and peak polarization Jp (2 mT – 200 mT) up to T = 160 °C. Appropriately enhanced impurity contents are shown to induce further decrease of the energy loss in materials already prepared for best performance at high temperatures (140 – 160 °C). This behavior can be hardly ascribed to the impurity-related increase of the electrical resistivity brough about by extra-doping, being it rather connected to a corresponding monotonical decrease of the effective magnetic anisotropy < Keff > with T. The decreasing anisotropy makes the balance between the contributions of domain wall (dw) displacements and reversible rotations to the magnetization process evolving in favor of the latter. The energy loss correspondingly develops with frequency and peak polarization in a complex fashion, according to the specific dissipative mechanisms sustained by the spins precessing either inside the moving walls or in the bulk. A dividing line in the (Jp − f) plane is identified, which separates dominant dw- and rotation-generated losses. It moves downward (i.e. lower f) with increasing temperature, the higher T the lower the frequency at which the rotations, theoretically assessed via the Landau-Lifshitz equation, supersede the domain wall contribution. Once accomplished, however, the transition to rotations can lead, according to the theoretical model, to higher losses when moving to higher temperatures. Following the experimental trend of the complex resistivity versus frequency at different T values, the calculations and the experiments show that eddy currents start to contribute to the energy loss, in the 5 mm thick ring samples, around a few MHz, accounting for about 50 % of measured loss beyond some 50 MHz. The chief dissipative process at applicative frequencies and induction values is therefore identified with spin damping, to which the generalized loss decomposition method can be applied.

The effect of hydrostatic stress on magnetic properties of Mn-Zn power ferrites at varying excitation levels

The effect of hydrostatic stress on magnetic properties of Mn-Zn power ferrites at varying excitation levels

Substitution of Sn in the high-permeability MnZn ferrite for wide temperature applications

To meet the challenge of varied working temperatures of inductance components in new energy vehicle and 5G communication, the high-TC high-permeability MnZn ferrite with excellent temperature stability was developed by the addition of SnO2. In this series of samples, initial permeability μi maintains large values in a wide temperature range. With increasing the SnO2 content, the temperature of the second permeability peak Tsp decreases and meanwhile Curie temperature TC maintains as high as 160 °C. For the best sample with 6000 ppm SnO2, μi 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 SnO2 generates Fe2+ and adjusts the magneto-crystalline anisotropy constant K1 = 0 point, which is responsible for the wide-temperature high permeability. The effect of SnO2 addition on magnetization process has also been clarified.

The effect of BaTiO3 on the magnetic behavior of MnZn ferrites at frequencies > 5 MHz

In this article an extensive study is presented on the effect of BaTiO3 on the high frequency performance of MnZn ferrite having a nominal composition Mn0.9Zn0.1Fe2.45O4. It is shown that BaTiO3 at an optimum concentration of 200 ppm wt. is a bulk dopant that dissolves in the spinel lattice leading to microstructures with smaller grain sizes, lower grain boundary resistivities and higher resonance frequencies. Despite an observed increase on the hysteresis losses, the main impact on the magnetic performance is the significant reduction of the high frequency resonance losses. In addition, no dependency has been observed on the particle size of BaTiO3 since nanoparticles produce the same effects as microparticles. Through exploitation of the beneficial effects of BaTiO3, MnZn ferrites with power losses of 195 kW m−3 (5 MHz, 10 mT, 100 °C) or 1125 kW m−3 (10 MHz, 10 mT 100 °C) and a relative initial permeability of 200 could be synthesized. These results belong to the best reported in literature and indicate that the application region of MnZn ferrites can be extended up to application frequencies traditionally dominated by other ferrite material families.

Mn–Zn ferrite foam concrete: Enhanced electromagnetic wave absorption and pore structure by incorporating carbon fibers

In this study, an absorbent composite of carbon-fibre-reinforced Mn–Zn ferrite foam concrete was fabricated. The influence of carbon fibre (CF) concentration on the mechanical and electromagnetic wave (EMW) absorption characteristics of Mn–Zn ferrite foam concrete within the 0.2–5GHz were investigated. Key performance indicators, such as compressive and flexural strengths, electromagnetic parameters, reflection loss, and absorption bandwidth were thoroughly analysed. The pore size and distribution were examined by X-ray computed tomography (CT) to reveal the EMW absorption mechanism. The findings indicate that CF effectively mitigates agglomeration in Mn–Zn ferrites, enhancing dielectric and magnetic losses synergistically, which improves not only the mechanical properties but also the EMW absorption capacity of Mn–Zn ferrite foam concrete. The optimal wave absorption performance was observed at a CF content of 0.3 wt%, yielding an impressive absorption bandwidth of 1.46 GHz and a minimum reflection loss (RLmin) of −28.75 dB. A noteworthy observation was the inverse correlation between the CF doping level and resistivity. The attenuation constant peaked at 108.13. When the CF content reached 1.2 wt %, the composite attained its percolation threshold, manifesting a resistivity of 145.4 Ω·m.

Arguments on the estimation of V ion distribution at various sites contributing to saturation magnetization in Mn–Zn ferrites

Mn0.6Zn0.4VxFe2-xO4 (x = 0.00–0.10, in steps of 0.02) are synthesized by the solid-state reaction method with a sintering temperature of 1250 °C. X-ray diffraction of the samples confirms the formation of the spinel structure. The grain size is found to increase in morphological investigation of the surface of the samples. The distribution of cations upon vanadium doping in manganese zinc ferrites has not been widely studied before. This study highlights our attempt to formalize a cation distribution to explain our experimental results. Vanadium ions occupying B-sites in their trivalent form may explain the decreasing trend observed in the cell parameters and saturation magnetization, MS values. To support this, theoretical cell parameters and theoretical magnetic moments have been calculated.

Contribution of Magnetization Mechanisms in MnZn Ferrites with Different Grain Sizes and Sintering Densification

This study investigates the magnetization mechanisms in MnZn ferrites, which are key materials in high-frequency power electronics, to understand their behavior under various sintering conditions. Employing X-ray diffraction and scanning electron microscopy, we analyzed the microstructure and phase purity of ferrites sintered at different temperatures. Our findings confirm consistent spinel structures and highlight significant grain-growth and densification variabilities. Magnetic properties, particularly the saturation magnetization (Ms) and initial permeability (μi), were explored, revealing their direct correlation with the sintering process. The decomposition of magnetic spectra into domain-wall-motion and spin-rotation components offered insights into the dominant magnetization mechanisms, with the domain wall movement becoming increasingly significant at higher sintering temperatures. The samples sintered at 1310 °C showcased superior permeability and the least loss in our investigations. This research underscores the impact of sintering conditions on the magnetic behavior of MnZn ferrites, providing valuable guidelines for optimizing their magnetic performance in advanced electronic applications and contributing to the material science field’s understanding of the interplay between sintering, microstructures, and magnetic properties.

Effect of Al3+ doping on magnetic properties of Zn-Mn ferrite nanoparticles for magnetic induction hyperthermia

Magnetic induction hyperthermia with self-regulated temperature is an advanced technology capable of automatically regulating hyperthermia temperature through a magnetic phase transition, which has a promising application prospect. This paper investigated the effects of Al3+ doping on the magnetic properties and Curie temperature of Zn-Mn ferrite. The specific saturation magnetization and Curie temperatures of Zn0.5Mn0.5AlxFe2-xO4 (0 ≤ x ≤ 0.6) nanoparticles decrease linearly with increment of Al3+ content. The magnetic heating experiments exhibit that the synthesized nanoparticles can raise the temperature of agar phantom to above 42 °C and self-regulate the temperature below their Curie temperatures, demonstrating their potential for self-regulated temperature hyperthermia. Additionally, in vitro cell experiments confirm the nanoparticles’ good biocompatibility.

Thermomechanical properties of confined magnetic nanoparticles in electrospun polyacrylonitrile nanofiber matrix exposed to a magnetic environment: structure, morphology, and stabilization (cyclization).

Electrospun metal oxide-polymer nanofiber composites hold promise for revolutionizing biomedical applications due to their unique combination of electronic and material properties and tailorable functionalities. An investigation into the incorporation of Fe-based nanofillers for optimizing the polyacrylonitrile matrix was conducted, where the systematic and organized arrangement of inorganic components was achieved through non-covalent bonding. These carefully dispersed nanomaterials exhibit the intrinsic electronic characteristics of the polymers and concurrently respond to external magnetic fields. Electrospinning was utilized to fabricate polyacrylonitrile nanofibers blended with Fe2O3 and MnZn ferrite nanoparticles, which were thermomechanically, morphologically, and spectroscopically characterized in detail. With the application of an external magnetic field in the course of dynamic mechanical measurements under tension, the storage modulus of the glass transition T g of PAN/Fe2O3 rises at the expense of the loss modulus, and a new peak emerges at ∼350 K. For the PAN/MnZn ferrite nanofibers a relatively larger shift in T g (from ∼367 K to ∼377 K) is observed, emphasizing that in comparison to Fe2O3, Mn2+ ions in particular enhance the material's magnetic response in MnZn Ferrite. The magnetic oxide particles are homogenously dispersed in polyacrylonitrile, corroborated by high-resolution scanning electron microscopy. Both nanopowder additions lead to a slight shift of the peak towards larger angles, related to the shrinkage of the polymer. Produced nanofibers with high mechanical and heating efficiency can optimize the influence of the intracellular environment, magnetic refrigeration systems and sensors/actuators by their magnetic behavior and heat generation.