Remanent Magnetization Mr Research Articles

Nanocrystalline Fe(Co)ZrMoBCu soft magnetic alloys: A transmission electron microscopy study of the microstructures

Nanocrystalline Fe81Zr7Mo2B9Cu1 and Fe40.5Co40.5Zr7Mo2B9Cu1 alloy ribbons were prepared by annealing the as-quenched amorphous alloys at their first exothermic peak temperature. The primary crystallization phases of Fe81Zr7Mo2B9Cu1 and Fe40.5Co40.5Zr7Mo2B9Cu1 consisted of nanoscale body-centered cubic α-Fe and α-FeCo grains, respectively. The microstructures and compositions were analyzed via transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM), and area maps were obtained through energy-dispersive spectroscopy (EDS). The addition of Co decreased the mean grain size (D) and broadened the grain-size distribution (σ). The effect of the addition of Co on the Cu clusters and element distribution was studied in detail. Scanning transmission electron spectroscopy combined with energy-dispersive spectroscopy revealed that both alloys contained Cu clusters; the Fe40.5Co40.5Zr7Mo2B9Cu1 alloy exhibited a Cu-cluster density similar to that of the Fe81Zr7Mo2B9Cu1 alloy. Both alloys contained relatively less Fe in their residual amorphous phases than in their nanocrystals, with the nanocrystals in Fe40.5Co40.5Zr7Mo2B9Cu1 containing less Co than in the residual amorphous phase. Fe40.5Co40.5Zr7Mo2B9Cu1 exhibited higher specific saturation magnetization (Ms), specific remanent magnetization (Mr) and larger coercivity (Hc) than Fe81Zr7Mo2B9Cu1.

Structural, magnetic, impedance and electric modulus response and dielectric relaxation in Co-doped inverse spinel [formula omitted] nanoferrite

In this research work, we report synthesis, structural, electric and magnetic properties of Cu1−XCoXFe2O4(x = 0.05, 0.10, 0.15, 0.20) nanoferrite. All the samples are synthesized using sol-gel auto-combustion method. X-ray diffraction patterns validate the formation of single phase tetragonal structure at room temperature for all the samples. Absence of secondary phases confirms the successful substitution of Cu2+ by Co2+ ions in CuFe2O4 matrix. Dielectric analysis reveals that all the materials exhibit remarkable single dielectric relaxation. The dielectric relaxation peaks are observed between 150–225 °C. In addition, Co-doped CuFe2O4 exhibit marked enhancement of dielectric constant value for potential technological applications. Further, the correlated barrier hopping (CBH) model well explains the conduction phenomena in all the samples. Activation energy values are analyzed by applying the Arrhenius equation. Impedance analysis indicates that both grain and grain boundary effects contributed the electrical response in the ferrites which is confirmed from the plot of Z″ vs. Z′. The bulk and grain boundary response are further determined by modeling the impedance data with an equivalent circuit. Modulus study confirms the existence of non-Debye type of relaxation in the synthesized ferrites. Magnetic study shows the improved value of magnetic parameters such as saturation magnetization (Ms), remanent magnetization (Mr) and coercive field (Hc).

Adjusting the gas detection characteristics of NiFe2O4 spinel ferrite nanoparticles through the introduction of Zn doping

Nickel ferrite nanoparticles doped with zinc were synthesized at a lower reaction temperature of 180 °C. The research delved into their structural, optical, dielectric, and magnetic properties. These nanoparticles exhibited a distinct cubic spinel structure, with crystallite sizes ranging from 33 to 51 nm. FTIR analysis revealed metal oxide stretching vibrations between 400–600 nm. FESEM and HR-TEM examinations unveiled irregularly shaped nano-particles. XPS analysis disclosed the chemical states of Zn2+, Fe3+, and Ni2+ ions. Mossbauer spectra exhibited two sextet patterns related to tetrahedral (A) and octahedral (B) sites, plus a weak doublet pattern. Magnetic tests showed a decrease in saturation magnetization (Ms) but an increase in remanent magnetization (Mr) and coercivity (Hc) values upon doping.

Effect of Cu substitution on magnetic and photocatalytic properties of Mn–ZnFe2O4 nanoparticles

The citrate approach was employed to successfully synthesize Mn0.4Zn0.6−xCuxFe2O4 (MZCF) with a nanostructured shape. A thorough examination was conducted on the microstructural, magnetic, and optical properties of the nanoparticles obtained. The X-ray diffraction (XRD) patterns revealed that all of the compositions exhibit a high degree of single-phase spinel formation. The experimental findings indicate that the introduction of copper ions leads to a reduction in both lattice constant and porosity, while concurrently resulting in an increase in the theoretical X-ray and bulk densities. The analysis of UV–Vis spectroscopy indicated that MZCF exhibited a direct band gap falling within the range of 1.61–1.78 eV. The magnetic characteristics were assessed through the analysis of hysteresis plots. The introduction of copper (Cu) content leads to notable improvements in the saturation (Ms) and remanent magnetization (Mr) values, which range from 40.21 to 58.78 and 4.46–10.54 emu/g, respectively. The assessment of the microwave frequency response has verified the appropriateness of MZCF nanoferrites for application within the frequency spectrum spanning from 8 to 13 gigahertz. The nanoparticles exhibit improved magnetic properties, suggesting their potential appropriateness for applications involving high-frequency microwave absorption and switching. Furthermore, the nanoparticles Mn0.4Zn0.6Fe2O4 and Mn0.4Zn0.2Cu0.4Fe2O4 were subjected to analysis utilizing a solar light simulator in order to induce degradation of MB dye.

Electrospun Cu-Co ferrite nanofibers: synthesis, structure, optical and magnetic properties, and anti-cancer activity.

In this study, we investigated Cu-Co ferrite nanofibers (NFs) that were synthesized for the first time employing the electrospinning technique. The structure, phase purity and crystallite size of all the prepared NFs were revealed by powder X-ray diffraction (PXRD) analysis. The NFs crystallized in the Fd3̄m (no. 227) space group and the cation distribution arrangement over distinct sites in their structure was analyzed. Scanning electron microscopy (SEM) together with energy-dispersive X-ray (EDX) spectroscopy analysis showed the microstructure of the NFs and verified their expected chemical compositions. High-resolution transmission electron microscopy (TEM) images confirmed the fibrous nature and the construction of the NFs. The band gap energies derived from the UV-vis reflectance spectra showed a blue shift with an increase in the amount of Cu in the sample from 1.42 eV to 1.86 eV. Magnetization (M) as a function of magnetic field (H) measurements performed at ambient and low temperatures showed the ferrimagnetic behavior of all the NFs. The magnetic parameters including coercivity (Hc), saturation magnetization (Ms), remanent magnetization (Mr), and squareness ratio were determined from the recorded magnetization curves. At 300 K, Ms was reduced from 78.8 to 42.4 emu g-1, Mr reduced from 22.8 to 7.6 emu g-1 and the Bohr magneton reduced from 3.3 to 1.8μB with an increase in the content of Cu in the samples. The same trend was observed at 10 K, where Ms was reduced from 93.7 to 50.9 emu g-1, Mr reduced from 60.9 to 35.9 emu g-1 and the Bohr magneton reduced from 3.94 to 2.16μB. Alternatively, Hc has the highest values for x = 0 (850 Oe at 300 K and 5220 Oe at 10 K) and x = 0.6 (800 Oe at 300 K and 5400 Oe at 10 K). The anti-cancer activity of the NFs was evaluated using the MTT cell viability assay, showing a reduction in the viability of both HCT-116 and HeLa cancer cells compared to non-cancerous HEK-293 cells after treatment with the NFs. Apoptotic activity was examined by DAPI staining, where treatment with the NFs induced chromatin condensation and nuclear disintegration in HCT-116 cells.

Enhanced Magnetic Properties of Gd-Doped ZnO by Varying the Gd Concentration via Co-Sputtering Technique

This study reports on the effect of Gd concentrations on the properties of Gd-doped ZnO films. The films were prepared using co-sputtering method at room temperature. Characterization tools such as X-ray diffraction (XRD), atomic force microscopy (AFM), and vibrating sample magnetometer (VSM) were used to analyze the properties of the prepared films. XRD results observed that all the films are well crystalline and designated to the hexagonal wurtzite structure of ZnO with no secondary phases, which confirmed the successful of doping the Gd into ZnO. Topography analysis from AFM discovered the increase of Gd concentrations of Gd-doped ZnO films leads to the increase in grain size and rougher surface of the films. The magnetization of the films effectively depends on the Gd concentrations, which the diamagnetic behavior changed to ferromagnetic behavior upon Gd doping. A film with higher Gd doping concentration is more effective than lower Gd doping in terms of saturation magnetization (Ms), coercivity (Hc) and remanent magnetization (Mr). These findings revealed that optimizing the Gd concentration is very crucial in enhancing the magnetic properties of Gd-doped ZnO films.

SYNTHESIS AND CHARACTERIZATION OF MAGNETITE FE3O4 NANOPARTICLES FROM NATURAL IRON SAND in GELAR RIVER

Fe3O4 nanoparticles made from the natural iron sands of the Gelar River have been successfully synthesized using the coprecipitation method. Test the content of Fe elements in pure iron sand and characterize them using XRF after separation. Fe3O4 nanoparticle characterization uses XRD to determine the sample's lattice parameters and crystal size. The nanoparticles' morphology, structure, particle shape, and elemental content were characterized using SEM-E DX. Magnetic properties and magnetic saturation values are characterized using VSM. XRF yield on iron sand before separation contains Fe 59.46%. After separation, the Fe content rose to 84.72%. The synthesis results obtained brownish-black Fe3O4 nanoparticle powder that permanent magnets can attract. Based on the XRD results, the crystal structure formed is cubic inverse spinel with crystal lattice Å with a particle size of 14.8 nm. The SEM-EDX results show the morphology of spherical nanoparticles with multiple agglomerations. Particle size is 40 nm. The EDX spectrum confirmed the formation of Fe3O4 nanoparticles in the presence of Fe (51.79%) and O (25.68%). The VSM results show that Fe3O4 samples have ferromagnetic properties with saturation magnetization (MS) = 27.36 emu/g, remanent magnetization (Mr) = -0.01 emu/g, and coercivity field (Hc) = 0.01 T.

Magnetic properties and electron oxidation state transition of immunomagnetic nanoparticles specifically captured with the target bacteria

Immunomagnetic nanoparticles (IMNPs) have been widely applied for the capture and concentration in the rapid detection of target bacteria. In this research, the focus was on studying the changes in magnetic properties changes of the IMNPs when they were attached to bacterial cells. These alterations in properties could facilitate an even rapid detection of the target bacteria and eliminate the need for culturing on plating media. The variation of magnetizing values, including saturated magnetization (Ms), remanent magnetization (Mr), coercivity force (Hc), and magnetic susceptibility (χm), was analysed through M-H loops. It was observed that the magnetizing properties of the IMNPs underwent changes based on the concentrations of Salmonella Typhimurium cells in the test solution. The correlation of this phenomenon was confirmed by the results of synchrotron x-ray absorption spectroscopy (XAS), which revealed electronic transition changes in the IMNPs after capturing the bacteria cells. Additionally, the electronic bands of the magnetite nanoparticle [Fe(II) and Fe(III)] were detected, indicating an electronic transformation between the Salmonella cells and the bound IMNPs. The XAS change was further verified using different cell types, such as Campylobacter jejuni which also showed electronic transformation after attaching to IMNPs. These findings suggest that IMNP-cell attachment triggered the change in the magnetic properties of IMNPs. Such insights could serve as valuable information for the development of novel rapid bacteria detection assays/devices using magnetic sensing techniques.

Moist Heat Synthesis of Magnetic EGCG-Cappedα-Fe2O3 Nanoparticles and Their In Vitro and In Silico Interactions with Pristine HSA- and NDM-1-Producing Bacteria.

A simple, facile, moist-heating (e.g., autoclave), one-step procedure for EGCG-mediated biosynthesis of narrow-size magnetic iron oxide (α-Fe2O3) nanoparticles (EGCG-MINPs) was developed. The influence of pH of the reaction mixture over the size distribution of as-synthesized EGCG-MINPs was investigated systematically by employing UV-visible (UV-vis) spectroscopy and dynamic light scattering (DLS)-based hydrodynamic size, surface charge (zeta-potential), and polydispersity index (PDI). The FE-SEM, TEM, and XRD characterizations revealed that the EGCG-MINPs synthesized at pH 5.0 were in the size range of 6.20-16.7 nm and possess well-crystalline hexagonal shaped nanostructures of hematite (α-Fe2O3) crystal phase. The role of EGCG in Fe3+ ion reduction and EGCG-MINP formation was confirmed by FTIR analysis. The VSM analysis has revealed that EGCG-MINPs were highly magnetic nanostructures with the hysteretic feature of saturation magnetization (Ms), remanent magnetization (Mr), and coercivity (Hc) as 33.64 emu/g, 12.18 emu/g, and 0.33 Oe, respectively. Besides, significant (p < 0.001) dose-dependent (250-1000 μg/mL) antibacterial and antibiofilm activities against the NDM-1-producing Gram-negative Escherichia coli (AK-33), Klebsiella pneumoniae (AK-65), Pseudomonas aeruginosa (AK-66), and Shigella boydii (AK-67) bacterial isolates warranted the as-synthesized EGCG-MINPs as a promising alternative for clinical management of chronic bacterial infections in biomedical settings. In addition, molecular docking experiments revealed that compared to free Fe3+ and EGCG alone, the EGCG-MINPs or Fe-EGCG complex possess significantly high binding affinity toward HSA and hence can be considered as promising biocompatible nanodrug carriers in in vivo drug delivery systems.

Structural and Magnetic Properties of MnxZn1-xFe2O4 Prepared via Sol-Gel Method

Manganese-zinc ferrite MnxZn1-xFe2O4 (MnZnF) powder was prepared using the sol-gel method. The morphological, structural, and magnetic properties of MnZnF powder were studied using X-ray diffraction (XRD), atomic force microscopy (AFM), energy dispersive X-ray (EDX), field emission-scanning electron microscopes (FE-SEM), and vibrating sample magnetometers (VSM). The XRD results showed that the MnxZn1-xFe2O4 that was formed had a trigonal crystalline structure. AFM results showed that the average diameter of Manganese-Zinc Ferrite is 55.35 nm, indicating that the sample has a nanostructure dimension. The EDX spectrum revealed the presence of transition metals (Mn, Fe, Zn, and O) in Manganese-Zinc Ferrite. The FE-SEM results of MnZnF showed uniform spherical structures. VSM was used to study the change in magnetization, the saturation magnetization, (Ms) value of the samples. The measurement of VSM indicated that the MnZnF exhibits ferromagnetic behavior with coercivity Hc (0.0014 Gauss), remanent magnetization (Mr) (0.202 emu/gr), and saturation magnetization Ms (2.69 emu/g).

Tuning the gas sensing properties of spinel ferrite NiFe2O4 nanoparticles by Cu doping

Copper substituted nickel ferrite nanoparticles (NiFe2O4) nanoparticles were prepared using hydrothermal technique at lower reaction temperature (175 °C). The structural, optical, dielectric, and magnetic properties were analyzed. The prepared nanopowders exhibited single phase-cubic spinel structure with a mean crystallite size in a narrow range 30–41 nm. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed the presence of stretching vibration of metal oxide in the range 400–600 nm. Field Emission Scanning Electron Microscopy (FESEM) and High Resolution-Transmission Electron Microscopy (HR-TEM) observations showed non-uniform cuboidal shaped nano-sized particles. The chemical and oxidation state of the constituents were revealed by X-ray photoelectron spectroscopy (XPS) (Cu2+, Fe3+ and Ni2+). Mössbauer spectra manifested two sextet patterns attributed to tetrahedral (A) and octahedral (B) sites with a doublet pattern of low intensity. Magnetic measurement revealed the decrease of saturation magnetization (Ms) value and increase of remanence magnetization (Mr) and coercivity (Hc) values while doping. A higher specific capacitance was obtained for x = 0.5 (1417 F/g) with a pseudocapacitive behavior. At room temperature, Liquefied Petroleum Gas (LPG) showed high selective response (1300 s for 250 ppm) compared to other tested gases.

Synthesis of ferromagnetic material nano powder and study of its effect on antibacterial activity

This work is to synthesize the cobalt ferrites nano powder of with the stoichiometric formula CoxFe2O4 (x= 0.8 and 1.4) by using sol-gel auto combustion method , and study structural and magnetic properties, the ferrite powders were calcined at 500, 600, and 700 °C for 3 hrs to remove organic waste and increase homogeneity and, The XRD diffraction analysis for CoxFe2O4 nanoferrites with single spinel structure. The crystal size of the formed crystallite of ferrite specimens increases with increasing temperature calcination and cobalt content , (FE-SEM) shows agglomerated with homogenous spherical and polyhedral particles. proportion of each of Fe ,Co, and O in all specimens is confirmed using the Energy Dispersive Spectrum (EDS),the magnetic characteristics are measured with a VSM. The remanence magnetization (Mr) saturation magnetization(Ms), and magnetic moment (nB) of CoxFe2O4 nanoferrites are found to go up with increasing calcination temperature, and E-coli bacteria were used to examine the inhibition of each ferrite using the diffusion-drilling agar method, as it is known that these nano powder possess therapeutic efficacy for numerous diseases.

Investigation on the structural, morphological and magnetic properties of Ca1-xEuxFe12-yTiyO19 hexaferrite system

M-type hexaferrites have a significant economic impact, due to their permanent magnet behaviour which plays key role in the conversion of renewable and green energy. The present investigation focuses on the synthesis of M-type Ca1-xEuxFe12-yTiyO19 hexaferrite (0.00 ≤ x, y ≤ 0.07) through the solid-state reaction method. The X-ray diffraction, Fourier Transform Infrared spectra and Raman spectroscopy confirms the presence of an M-type hexagonal structure unequivocally with the minor impurity of α-Fe2O3. Using Field Emission Scanning Electron Microscopy images reflects the surface morphology and anticipated grain size was within the range of 1.65–2.26 μm. Energy-dispersive X-ray analysis and High-Resolution X-ray photoelectron spectroscopy (HRXPS) confirms the elemental composition and the oxidation states of the elements by HRXPS. The magnetic characteristics is focused around the examination of physical phenomena and rigorous application of theoretical calculations of coercivity Hc, remanent magnetization Mr, saturation magnetization Ms, magneton number ηβ, squareness ratio (SQR) Mr/Ms ≤ 0.5 and Anisotropy constant Ka. The obtained samples exhibit a notable phenomenon of inter-grain group interaction and the compatibility of the material under investigation with high-frequency devices and its potential as high-density recording media.

Structural and magnetic properties of Sb substituted LTP Mn-Bi annealed ribbons

We optimized the composition of Mn-Bi alloy, examined the effects of third element substitution of Sn, Cu, Al, and Sb on the magnetic properties, and investigated the microstructures and magnetic properties of Sb substituted Mn-Bi annealed ribbons. The optimized composition was Mn54Bi46, and it was found that the Sb substitution had the most positive effects on the magnetic properties among the substitution elements. Thus, we accomplished a detailed investigation on Mn54Bi46-xSbx (0.0 ≤ x ≤ 5.0) annealed ribbons. The fracture planes of the annealed ribbons revealed that the grain size drastically decreased from a few tens of microns to submicrons close to the single domain size, which substantially enhanced the coercivity (Hc), remanent magnetization (Mr), and maximum energy product ((BH)max). As a result, as the Sb content changed from 0 to 1.5, the Mr, Hc, and (BH)max of randomly oriented samples increased significantly from 14.7 emu/g, 0.50 kOe, and 0.15 MGOe to 37.2 emu/g, 8.15 kOe, and 3.27 MGOe, respectively. Furthermore, the temperature dependence of Hc on the Sb substitution showed significant enhancement over a wide temperature range from 223 to 378 K, suggesting that Mn-Bi alloy can be used in electrical vehicles.

Enhanced photodegradation of CuCo2O4 nanoflower for the dye degradation of Rhodamine B and Methyl Violet

The investigation examined into the effect of different hydrothermal reaction temperatures and durations on the formation of nanoflower-shaped CuCo2O4 nanostructures (CCO NPs). The structural, morphological, functional, optical, and magnetic properties of the synthesized CCO NPs were thoroughly examined. The optimal calcination temperature was determined using Thermogravimetric and Differential Thermal Analysis (TG/DTA), which identified 400 °C as the ideal temperature. Following X-ray Diffraction (XRD) analysis, pure CuCo2O4 samples were formed, with calculated average crystallite sizes of 27 nm for CCO-A, 48 nm for CCO-B, 30 nm for CCO-C, and 31 nm for CCO-D samples. Fourier Transform Infrared (FTIR) analysis provided additional confirmation of pure CuCo2O4 formation, with characteristic bands in the 665–662 cm-1 and 583–567 cm-1 ranges indicating the presence of CuO and CoO bonds. SEM, High-Resolution SEM (HRSEM) and High-Resolution Transmission Electron Microscopy (HRTEM) all supported the observation of a distinct flower-like structural morphology. The optical properties of an optimized sample were revealed by UV–Visible Diffuse Reflectance Spectroscopy (UV-DRS) analysis, which revealed a band gap of 3.3 eV. According to Vibrating Sample Magnetometer (VSM) results, the magnetic behavior of CCO-D nanostructures at room temperature exhibited paramagnetic characteristics. The saturation magnetization (Ms), remanent magnetization (Mr) and coercivity (Hc) values were determined to be 0.26218 emu/g, 2.7214 × 10–3 emu/g and 29.787 Oe, respectively. To evaluate photocatalytic performance, the CCO-D photocatalyst was used to degrade Methyl Violet and Rhodamine B dyes. CCO-D degraded MV dye with greater efficiency (93%) than RhB (85%) when exposed to sunlight. These findings highlight CCO-D's potential as a photocatalyst for the degradation of organic dyes.

Exploration on the Structural, Optical, Morphological and Magnetic Properties of Hematite Nanoparticles and Their Antibacterial Activity

Hematite (α-Fe2O3) nanoparticles have been prepared by the conventional chemical precipitation synthesis technique. The prepared samples were subjected to structural, morphological, optical, magnetic and antibacterial behaviours. The diffraction analysis implies that the measured crystallite size of α- Fe2O3 nanoparticles is found to be 39 nm. The UV-visible absorption spectroscopy exhibits a strong absorption around 560 nm which is characteristics of Fe2O3 nanoparticles and the calculated bandgap value is found to be 2.07 eV. The presence of iron oxide polymorphs can be demonstrated by displaying phonon modes in Raman spectroscopy. Fourier-transform infrared spectroscopy (FTIR) study is used to identify the existence of functional groups and chemical structure of the synthesised Fe2O3 nanoparticles. Magnetic analysis displays hysteretic behaviour at room temperature with saturation magnetization Ms = 0.0036 emu/gm, the remanent magnetization Mr = 0.000698 emu/gm, and coercivity Hc = –0.27 Oe, respectively. The antibacterial activities of these α-Fe2O3 nanoparticles were investigated on pathogenic bacteria Pseudomonas aeruginosa, Bacillus cereus, Staphylococcus aureus, and E. coli by a zone of inhibition method.

Ferroelectric, Magnetic and Dielectric Properties of SrCo0.2Zn0.2Fe11.6O18.8 Hexaferrite Obtained by “One-Pot” Green Sol-Gel Synthesis Utilizing Citrus reticulata Peel Extract

SrCo0.2Zn0.2Fe11.6O18.8 hexaferrite was obtained by a “one-pot” green sol-gel synthesis method utilizing aqueous mandarin orange (Citrus reticulata) peel extract as an eco-friendly reactant. The research objective was to analyze the influence of cobalt and zinc co-doping and the synthesis process on the structure, morphology, magnetic, dielectric and ferroelectric properties of strontium hexaferrite in view of future applications. Structural and morphological characterization using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy coupled to energy dispersive X-ray spectrometry (SEM-EDX) confirmed the formation of a Co and Zn ion incorporated M-type magnetoplumbite with c/a lattice parameter ratio of 3.919 as crystallite nanoplatelets of 32 and 53 nm in thickness and width, respectively. The magnetic hysteresis loop of the synthesized powder recorded by a vibrating sample magnetometer (VSM) at room temperature confirmed its ferromagnetic nature with a coercive field (Hc) of 2539 Oe and a saturation magnetization (Ms) and remanent magnetization (Mr) of 44.6 emu/g and 21.4 emu/g, respectively. Room temperature ferroelectric loops measured at 100 Hz showed a maximal (Pmax) and a remanent (Pr) polarization of 195.4 and 31.0 nC/cm2, respectively. Both increased when the magnitude of the applied electrical field increased in the 1–24 kV/cm range. The dielectric constant decreased with the frequency increase, in accordance with the Maxwell–Wagner model, while the conductivity changed according to the Jonscher power law. The complex impedance was modeled with an equivalent circuit, enabling identification of the dominant contribution of grain boundary resistance (272.3 MΩ) and capacitance (7.16 pF).

Properties of Sm–Mn substituted M-type strontium ferrites synthesized by the sol-gel method

M-type strontium ferrites Sr1-xLnxFe12-xMxO19 (Ln: Sm; M: Mn; x = 0, 0.03, 0.06, 0.09, 0.12) doped with equivalent Sm-Mn ions were synthesized via the sol-gel method. The products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electric microscopy (SEM) and vibrating sample magnetometer (VSM). The samples with x from 0.00 to 0.12 were confirmed to the single-phase M-type strontium ferrite, and the impurity phases Fe2O3 and SmFeO3 were detected when the content of dopants x ≥ 0.09. When x = 0.09, the saturation magnetization (Ms) and the remanent magnetization (Mr) of strontium ferrites Sr1-xSmxFe12-xMnxO19 reached to the maximum values of 37.19 emu/g and 22.48 emu/g, respectively. When x = 0.06, the coercive force (Hc) of strontium ferrites Sr1-xSmxFe12-xMnxO19 reached to the maximum values of 6224 Oe. Acid-treatment reduces the magnetic properties of the Sr1-xSmxFe12-xMmxO19 (x = 0.03). Compared to 950 °C preparation, preparation at 1200 °C decreases its magnetic properties and the Hc drop is very significant.

Investigation of the structural, electrical and magnetic properties of vanadium substituted Mn–Zn ferrites

This work revealed the role of altering vanadium (V) content in Mn–Zn ferrites. We used the traditional solid-state reaction method to prepare the {mathrm{Mn}}_{0.5}{mathrm{Zn}}_{0.5}{mathrm{V}}_{mathrm{x}}{mathrm{Fe}}_{2-mathrm{x}}{mathrm{O}}_{4} (x = 0.0, 0.05, 0.10, 0.15, 0.20) ferrites. Powder X-ray diffraction was used to analyze the samples’ crystal structures, revealing the prepared sample’s spinal cubic crystal structure. With increasing Vanadium concentration, the lattice constant drops proportionately. We used Debye–Scherrer (D–S), Williamson–Hall (W–H) Plot, Halder–Wagner (H–W) Langford, and Size Strain Plot (SSP) methods to compare different structural properties. We also used the impedance analyzer to investigate the samples’ dielectric characteristics and AC conductivity at room temperature over a frequency range of 1 kHz–100 MHz. The magnetic properties, i.e., Saturation magnetization (Ms), Coercive field (Hc), and Remanent magnetization (Mr), were estimated from the ferromagnetic hysteresis behavior of the samples measured using a vibrating sample magnetometer (VSM). The saturation magnetization was observed to decrease with an increase in V content. The Mr and HC vary non-linearly with V contents. The prepared samples’ initial permeability was tested, and a reasonably constant complex permeability (µ') was recorded over a wide frequency range (~ 1000 Hz).

Sol-gel synthesis, structural, morphological, X-ray photoelectron spectroscopy and magnetic properties of Cd doped BaTiO3 nanostructures

The present study reports the new functionality of room temperature ferromagnetism (RTFM) in non-magnetic Cadmium (Cd) doped BaTiO3 nanostructures, contrary to pure diamagnetic BaTiO3. TEM images show that grain size reduces with Cd doping. XPS analysis indicates that cation vacancies induce RTFM in Cd doped BaTiO3. Magnetic study reveals that pure BaTiO3 exhibits diamagnetic like signature, while Cd doped BaTiO3 show ferromagnetic feature with saturation magnetization (Ms ∼ 9.70x10-3 emu/g), remanent magnetization (Mr ∼ 0.22x10-3 emu/g) and coercive field (Hc ∼ 42.54 Oe), respectively. The current investigation also indicates that the induced RTFM could meet the demand of developing spintronic applications.