Decrease In Saturation Magnetization Research Articles

Investigation of Structural, Elastic and Magnetic Properties of CoCr2−xZrxO4 Nanoparticles

This study investigates the impact of zirconium substitution on the structural, elastic and magnetic properties of CoCr2O4 nanoparticles. A series of CoCr2−xZrxO4 nanoparticles, x = 0.00, 0.05, 0.10, 0.15 and 0.20, are synthesized via the co-precipitation method. X-ray diffraction (XRD) patterns affirm the formation of single-phase cubic structure with the space group Fd3m. Special attention is given to accurately calculating the average crystallite size (D) and lattice parameter (a) using Williamson–Hall (W–H) analysis and the Nelson–Riley (N–R) extrapolation function, respectively. The increase in Zr4+ content leads to a reduction in crystallite size and an increase in the lattice parameter. Elastic properties are estimated from force constants and the lattice constant, determined from FTIR and XRD, respectively. The observed changes in the elastic constants are attributed to the strength of interatomic bonding. The stiffness constants decrease, while Poisson’s ratio increases with increasing Zr4+ content, reflecting the increase in the ductility of the prepared samples. As the Zr4+ content increases, the stiffness constants decrease, and Poisson’s ratio increases, reflecting enhanced ductility of the samples. Furthermore, as Zr4+ content rises, Young’s modulus, the rigidity modulus and Debye temperature decrease. The magnetic hysteresis loop measurements are carried out at room temperature using a vibrating sample magnetometer (VSM) over a field range of 25 kg. Unsubstituted CoCr2O4 exhibits ferrimagnetic behavior. As Zr4+ content increases, saturation magnetization (Ms) and magnetic moment decrease, while remanent magnetization (Mr) and coercivity (Hc) initially decrease up to x = 0.10, then increase with further increases in x. The novel key of this study is how Zr4+ substitution in CoCr2O4 nanoparticles can effectively modify their elastic moduli and magnetic properties, making them suitable for various applications such as flexible electronics, protective coatings, energy storage components and biomedical implants.

Solvent-depended magnetic-field-induced synthesis of iron nanochains

This work presents a synthesis of iron nanochains through magnetic-field-induced reduction reaction performed with sodium borohydride in water, ethanol and isopropanol. After their preparation, the nanomaterials obtained in three different processes are washed several times in ethanol and acetone to remove side-products. The performed cleaning step is very sufficient for water-based synthesis of iron nanochains. In contrary, the nanostructures obtained in ethanol and isopropanol contain a significant amount of sodium chlorides which is hard to dispose. Moreover, the use of ethanol and isopropanol solvents causes the reduction of nanochains’ diameters. Both the presence of sodium chlorides and the reduction of diameter size result in the decrease of saturation magnetization of iron nanochains and the increase of their coercivities.

Tailoring Structural and Magnetic Properties: Cd²⁺ and Cu²⁺ Co-Doped Ni-Zn Ferrite Nanoparticles via Sol-Gel Auto-Combustion

In this research work, we have incorporated paramagnetic Cu2+ and diamagnetic Cd2+ cations in spinel ferrites. By adjusting the concentrations of Cu and Cd, it is possible to achieve a balance between enhanced electrical conductivity, desired magnetic properties, and suitable structural characteristics for applications in high-frequency devices, magnetic sensors, and electromagnetic interference (EMI) suppression through a synergistic effect. The sol-gel auto-combustion method was employed to synthesize Cd²⁺ and Cu²⁺ co-doped Ni₀.₅Zn₀.₅₋ₓ₋ᵧCuₓCdᵧFe₂O₄ (x = y = 0.0, 0.05, 0.1, 0.15, 0.2) ferrite nanoparticles. Structural, morphological-compositional, functional, and magnetic properties of the nanoparticles were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy with energy dispersive spectroscopy (FESEM-EDS), Fourier-transform infrared spectroscopy (FT-IR), and vibrating sample magnetometry (VSM). The XRD results confirmed the single-phase spinel structures with lattice constants increasing with higher dopant concentrations. The average crystallite sizes were found in the range of 38.14 - 42.68 nm and lattice constants in the range of 8.389 - 8.423 Å. Morphological analysis revealed agglomeration, consistent with the stoichiometric proportions during synthesis. There is a decreasing trend in nanograin sizes in the range of 40 to 73 nm with the concentration. FT-IR spectra verified the spinel structures through characteristic absorption bands around 600 cm⁻¹ and 400 cm⁻¹. Magnetic measurements indicated a decrease in saturation magnetization with increasing dopant levels indicating their potential use in electromagnetic wave absorption and magnetic memory devices.

Optimization of structural, optical, dielectric and magnetic properties of Gd3+ substituted Mg-Mn mixed spinel ferrite ceramics

Manganese magnesium ferrite (Mg0.5Mn0.5Fe2O4) and Gd doped Mg0.5Mn0.5Fe2O4 (Mg0.5Mn0.5Fe2-xGdxO4 (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5) were synthesized using the solid-state method. The structural study was performed using the powder X-ray diffraction (XRD) technique. The XRD plot confirms the presence of a spinel cubic structure for pure MgMn ferrite and the existence of a secondary GdFeO3 phase in addition to the cubic spinel phase for Gd-doped MgMn ferrite. The average crystallite size estimated from the Williamson-Hall plot decreases from 42.75 nm to 18.97 nm with the increase in Gd content. The microstructural study confirms the clear grains with well-defined grain boundaries. The Fourier Transform Infrared (FTIR) spectra of the samples show the vibrational bands at 3440 cm−1, 1636 cm−1, 1385 cm−1, 1100 cm−1, and 560 cm−1 assigned to tetrahedral and octahedral sites. The improvement in dielectric property has been observed for Gd-doped samples. The saturation magnetization and remnant magnetization decrease from 0.7 to 0.3 emu and 0.035 to 0.0273 emu respectively. The coercivity increases from 31 to 75 Oe with the increase in Gd content. The fabricated spinel ferrites have significant electrical and magnetic properties which may be promising candidates for microwave devices.

Role of surface roughness in determining surface energy and magnetic properties of Fe80Ce20 films during thermal processing on Si(100) and glass substrates

In this study, Fe80Ce20 films were deposited on Si(100) and glass substrates using sputtering in a high-vacuum environment and subsequently heat-treated in a vacuum annealing furnace. The films, with thicknesses ranging from 10 nm to 50 nm, were annealed at temperatures of 100 °C, 200 °C, and 300 °C. The objective was to investigate the effects of film thickness and annealing temperature on the structural, surface energy, and magnetic properties of the material. X-ray diffraction (XRD) analysis confirmed the crystalline nature of both Si(100)/Fe80Ce20 and Glass/Fe80Ce20 films. Atomic force microscopy (AFM) revealed a smooth film surface that became rougher after annealing. Contact angle measurements indicated hydrophilic properties, with the highest surface energy observed in the as-deposited films due to a higher density of defects and grain boundaries. The hysteresis loop demonstrated exceptional soft magnetic properties and a high saturation magnetization (Ms) of approximately 2000 emu/cm³. Annealing at 100 °C altered the magnetic domain structure from a striped labyrinthine configuration to an aligned pattern. At higher annealing temperatures, the films exhibited grain growth, increased surface roughness, and new grain formation. Following annealing, the grains in the Fe80Ce20 films became larger, surface roughness increased, and the water contact angle increased, rendering the films more hydrophobic. The as-deposited films displayed the highest surface energy due to the high density of defects and grain boundaries. Increased surface roughness led to more grain boundary defects and irregularities, which served as pinning points for magnetic domain walls, thus increasing coercivity (Hc). Rough surfaces induced local stress fields, increased magnetic anisotropy, and decreased saturation magnetization. Thermal perturbations from higher annealing temperatures further disrupted the alignment of the magnetic moments, leading to a reduction in saturation magnetization.

Sr doping effects on La(1-x)SrxMnO3-BaTiO3 nanocomposites: A comprehensive analysis of structural, optical, magnetic, and dielectric properties

Sol-gel synthesized La(1-x)SrxMnO3–BaTiO3 nanocomposites with varying strontium content were investigated to explore the influence of Sr doping on their properties. X-ray diffraction confirmed the perovskite phase purity. Sr doping resulted in a tunable bandgap, widening from 2.33 eV to 2.57 eV as Sr content increased, as revealed by Diffuse Reflectance Spectroscopy. Vibrating Sample Magnetometry measurements exhibited a Sr-dependent decrease in saturation magnetization (22 emu/g for x = 0.2 to 14 emu/g for x = 0.5). Dielectric analysis demonstrated an enhanced dielectric constant and the emergence of new relaxation behaviors with Sr doping. These findings unveil the tailorable optical, magnetic, and dielectric properties of LSMO-BTO nanocomposites due to Sr doping, suggesting their potential for diverse technological applications.

Impact of Co2+ substitution on structure and magnetic properties of M-type strontium ferrite with different Fe/Sr ratios

Abstract Ion substitution has significantly improved the performance of ferrite magnets, and cobalt remains a key area of research. Studies on the mechanism of Co2+ in strontium ferrite, especially SrFe2n–x Co x O19–δ (n = 6.1–5.4; x = 0.05–0.20) synthesized using the ceramic method, showed that Co2+ preferentially enters the lattice as the Fe/Sr ratio decreases. This results in a decrease in the lattice constants a and c due to oxygen vacancies and iron ion deficiency. The impact of Co substitution on morphology is minor compared to the effect of the Fe/Sr ratio. As the Fe/Sr ratio decreases and the Co content increases, the saturation magnetization decreases. The magnetic anisotropy field exhibits a nonlinear change, generally increasing with higher Fe/Sr ratios and Co content. These changes in the performance of permanent magnets are attributed to the absence of Fe3+ ions at the 12k + 2a and 2b sites and the substitution of Co2+ at the 2b site. This suggests that by adjusting the Fe/Sr ratio and appropriate Co substitution, the magnetic anisotropy field of M-type strontium ferrite can be effectively optimized.

Effect of substitution of aluminium and neodymium on structural and magnetic properties of yttrium iron garnet studied using 57Fe internal field NMR

The structural and magnetic properties of non-magnetic aluminium and magnetic neodymium substituted yttrium iron garnet samples (Y3-xAlxFe5O12 and Y3-nNdnFe5O12) were investigated. Powder samples were synthesized using auto combustion route. The Rietveld refinement analysis of the samples confirmed the presence of the garnet phase and showed presence of minimal impurity phases, specifically perovskite and hematite. Substitution on Y3Fe5O12 with Al resulted in a linear decrease in saturation magnetization, while Nd substitution showed a non-linear change. In accordance with this the Internal Field Nuclear Magnetic Resonance (IFNMR) spectrum exhibited a downward shift in peak frequency when Al was substituted, and a significant reduction in intensity with Nd substitution in yttrium iron garnet samples. Aluminium ions take up either tetrahedral or octahedral positions in the lattice, apart from the dodecahedral site, because of their smaller ionic radii. This causes a decrease in the hyperfine field that originates from Fe3+ ions in tetrahedral and octahedral sites. On the other hand, neodymium ions occupy dodecahedral sites and are expected not to affect Fe ions. Concurrently, an observable peak shift was not observed in the IFNMR spectrum for Nd substitution. However, Nd substitution introduced strain in the lattice due to their larger ionic radii compared to yttrium, which they replace. This strain causes disorder in tetrahedral and octahedral sites and affects 57Fe signal intensity. The magnetic properties observed from VSM analysis is also interpreted in view of observed changes in the 57Fe IFNMR spectrum. X-ray Photoelectron spectroscopy (XPS) was employed mainly to explore spin orbit splitting of Fe 2p state in the samples.

Modulation on the magnetic and electrical transport properties of Pr0.5Ba0.5MnO3-δ thin films by oxygen vacancies

In this work, the magnetic and electronic transport properties of the epitaxial Pr0.5Ba0.5MnO3-δ (PBMO) thin films via the modulation of the oxygen vacancies have been investigated. PBMO thin films were fabricated by pulsed laser deposition (PLD) at different oxygen ambient pressures (20, 50, 70, and 250 mTorr). From the XRD and STEM measurements, the oxygen vacancies content in the film increases with the decrease of growth pressure, leading to an expansion of the out-of-plane lattice constant of the film. The PNR (Polarized Neutron Reflectometry) was employed for a precise magnetization and oxygen stoichiometry depth profile of the PBMO thin films and further quantitatively characterize the oxygen vacancies’ content of the films. Thus, an increasing number of oxygen vacancies suppress the double exchange interaction and carriers hopping are suppressed, resulting in a significant increase in resistivity, as well as a decrease in saturation magnetization and ferromagnetic Curie temperature.

Praseodymium dysprosium co-doped M-type strontium ferrite: Intentionally manufacturing heterophase growth to improve microwave absorption performance

When excessive praseodymium and dysprosium ions are doped with M-type strontium ferrite, heterophases with different magnetic and electrical properties will be formed. We use this to intentionally induce different heterogeneous growth in the Pr–Dy co-doped strontium ferrite system. While maintaining the dielectric loss of the main phase, the produced heterogeneous phase acts as a companion for dielectric and magnetic losses. The synthesized SrFe12-2xPrxDyxO19 ferrite demonstrates its potential as a microwave absorbing material, exhibiting excellent absorption effects over a wide range of Pr–Dy doping (x = 0.05–1.5). The XRD results show that the synthesized materials include both pure M-phase and coexistence of M-phase and heterophases, and the generated heterophases are mainly perovskite type ferrite and garnet type ferrite. SEM and EDS results indicate that Pr–Dy co-doping can significantly refine the grain size, reduce the grain size of the main and heterophases, and lead to a decrease in oxygen content. The XPS analysis shows that some praseodymium ions are in the Pr4+ oxidation state, leading to the existence of Fe2+ ions and oxygen defects (Od). The VSM results indicate that at different calcination temperatures, the saturation magnetization decreases and the coercivity shows an increasing trend as the Pr–Dy doping amount increases. Pr–Dy doping not only increases the dielectric and magnetic losses of the M phase, but also generates heterophases that can enhance the dielectric and magnetic losses of the material, jointly improving the absorption effect. This results in excellent absorption performance of the material within a large range of praseodymium dysprosium doping contents (x = 0.05–1.5, RLmin = −52.51 dB, EABmax = 4.81 GHz).

Effect of rare earth (Ho and Er) co-substitution on the magnetic and dielectric properties of nanocrystalline cobalt ferrites

Nanocrystalline cobalt ferrites co-substituted with rare earth Ho and Er (CoFe2-2xHoxErxO4, 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 (Ms), magnetocrystalline anisotropy (K1), coercivity (Hc) and Curie temperature (Tc) with Ho–Er co-substitution. Electron Spin Resonance (ESR) exhibited asymmetric resonance peaks, reduced resonance field (Hr), linewidth (ΔHpp) and deviation in Lande g values. Impedance spectroscopy revealed two conduction mechanisms (holes and electrons) with distinct activation energies (EaI and EaII). 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 (σac) 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).

Effect of Sm2O3 additive on the microstructure, magnetic and electrical properties of LiTiZn ferrite ceramics

LiTiZn ferrites were prepared by a conventional two-steps solid sintering method. According to X-ray diffraction (XRD) results, the primary phase of all specimens was ferrite spinel. It is shown that Sm2O3 additive 1 wt% slightly reduces the lattice parameter of the spinel phase and leads to the appearance of an additional phase SmFeO3. For the first time for LiTiZn ferrite received, that Sm2O3 additive leads to significant increase of the electrical resistivity and the Curie temperature by 25°. Thus, the problem with dielectric loss reduction in the microwave and thermal stability increasing of ferrite ceramics was solved. At the same time, there is a 6 % decrease in saturation magnetization and 11 % in density while coercive force increases by the 60 %. In addition, scanning electron microscope (SEM) data show significant influence of Sm2O3 additive on grain morphology. The energy dispersive spectroscopy (EDS) patterns confirm SmFeO3 phase formation. The results of the study can be used for improvement of sintering ferrite products in a factory.

Phase Formation and Magnetic Properties of (Y1−xSmx)Co5 Melt-Spun Ribbons

Using X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM), the effects of Sm substitution, wheel speed, and annealing temperature on the phase formation and magnetic properties of (Y1−xSmx)Co5 (x = 0.2, 0.3, 0.4, 0.5) melt-spun ribbons were investigated. The results indicate the following: (1) With the increase in Sm substitution, it was found that (Y1−xSmx)Co5 ribbons are entirely composed of the (Y-Sm)Co5 phase with a CaCu5-type structure. Additionally, the coercivity gradually increases, while the remanence and saturation magnetization gradually decrease. (2) As the wheel speed increases, the (Y1−xSmx)Co5 ribbons exhibit an increasing proportion of (Y-Sm)Co5 phase until reaching a speed of 40 m/s, where they are entirely composed of the (Y-Sm)Co5 phase. Magnetic measurements show that the coercivity (Hcj) and remanence (Br) of (Y0.5Sm0.5)Co5 ribbons increase gradually with increasing wheel speed, while saturation magnetization decreases. The variation in magnetic properties is mainly attributed to the formation of nucleation centers for reversed magnetic domain (2:7 and 2:17 phases); (3) (Y0.5Sm0.5)Co5 ribbons are composed of the (Y-Sm)Co5 phase and a small amount of the Sm2Co7 phase after annealing at 550 °C, 600 °C, and 650 °C. Temperature elevation promotes crystallization of the amorphous phase, resulting in a gradual decrease in coercivity, while the remanence and saturation magnetization exhibit an overall increasing trend. Through continuous optimization of the process, favorable magnetic properties were achieved under the conditions of a 0.5 Sm substitution level, a wheel speed of 40 m/s, and an annealing temperature of 550 °C, with a coercivity of 7.98 kOe, remanence of 444 kA/m, and saturation magnetization of 508 kA/m.

Structure-Related Electronic and Magnetic Properties in Ultrathin Epitaxial NixFe3-xO4 Films on MgO(001).

Off-stoichiometric NixFe3-xO4 ultrathin films (x < 2.1) with varying Ni content x and thickness 16 (±2) nm were grown on MgO(001) by reactive molecular beam epitaxy. Synchrotron-based high-resolution X-ray diffraction measurements reveal vertical compressive strain for all films, resulting from a lateral pseudomorphic adaption of the film to the substrate lattice without any strain relaxation. Complete crystallinity with smooth interfaces and surfaces is obtained independent of the Ni content x. For x < 1 an expected successive conversion from Fe3O4 to NiFe2O4 is observed, whereas local transformation into NiO structures is observed for films with Ni content x > 1. However, angle-resolved hard X-ray photoelectron spectroscopy measurements indicate homogeneous cationic distributions without strictly separated phases independent of the Ni content, while X-ray absorption spectroscopy shows that also for x > 1, not all Fe2+ cations are substituted by Ni2+ cations. The ferrimagnetic behavior, as observed by superconducting quantum interference device magnetometry, is characterized by decreasing saturation magnetization due to the formation of antiferromagnetic NiO parts.

Study the Structural, Morphological and Magnetic Properties of (Bi Ni Fe2 O4/C) Nano Composite

In this work, bismuth nickel ferrite (Bix Ni1-x Fe2O4) supported by activated carbon (AC) with x=0, 0.3 and 0.5 were made and studied using the sol-gel method, and the samples were calcinated at 350 and 650 °C for 3 hours. XRD, FTIR, FESEM, and EDX spectroscopy were used to examine the chemical structure and morphology of bismuth nickel ferrite on activated carbon (Bix Ni1-x Fe2O4/ C). The XRD patterns show that when the temperature of the synthesized material is raised, the intensity and spread of the peaks decrease. This leads to more crystallization. FTIR studies were done in the frequency range (400–4000) cm-1, and the FTIR spectrum of (Bix Ni1-x Fe2O4/ C) shows the two significant absorption bands near the frequency ranges 500 cm-1 and 700 cm-1. FESEM with particles that were between 17 and 60 nm in size was used to study the surface morphology. The EDS plots revealed the existence of no extra peaks other than constituents of the taken up composition. The decrease in saturation magnetization (Ms) and remanence magnetization (Mr) is seen through the utilization of a vibrating sample magnetometer (VSM).

Study of iron ion distribution in rare earth (La, Pr, Sm, Dy) doped nickel-zinc spinel ferrites through Mössbauer spectroscopy

Ni0.5Zn0.5Fe1.95RE0.05O4 (RE=La, Pr, Sm, Dy) spinel ferrites were prepared using the sol-gel method. X-ray diffraction analyses revealed that doping with rare earth ions increases the lattice parameters of the ferrites, accompanied by a decreasing trend due to lanthanide contraction. Mössbauer spectrum showed that rare earth ion doping facilitates the migration of iron ions from B sites to A sites, with the extent of migration increasing alongside the atomic number of the rare earth elements. Vibrating sample magnetometer tests indicated a general decrease in saturation magnetization following rare earth ion doping. A comprehensive investigation into the effects of different rare earth ion dopings on the properties of Ni-Zn ferrites was conducted by calculating theoretical magnetic moments and comparing them with the experimentally measured values. This comparison elucidated the mechanism behind the magnetic alterations in rare earth-doped spinel ferrites, providing theoretical support for future magnetic modulation in these materials.

An insight into the structural, magnetic and dielectric properties of modified SrFe12-xPbxO19 (x = 0–0.3)

Effect of Pb2+ substitutions on the structural, magnetic and dielectric properties of SrFe12O19 in the form of SrFe12-xPbxO19 (x = 0, 0.1, 0.2 and 0.3) is carried out. All the samples crystalize in hexagonal magneto-plumbite structure with P63/mmc symmetry. An irregular but randomly distributed particles with average particle size increased from 0.791 μm to 1.131 μm due to substitutions. A characteristics Hopkinson peak is observed just below the transition temperature, may be stems from the superparamagnetic relaxations. The isothermal magnetization depicts an increase in coercivity (Hc) and decrease in saturation magnetization (Ms) due to Pb substitutions, which is further explained in the framework of site symmetry of the Fe and its multiple valence states. Mossbauer study reflects that, Fe3+/ Fe2+ present in the systems are associated with different electric environment. Furthermore, the shifting of dielectric transition by 50 °C upon substitutions is associated to dipole formation in presence of lone pair of Pb2+. A relaxor type of behavior is acquired by the system with a non-Debye type of relaxation is explained on the basis of complexity of the dipoles associated with each crystallographic sites.

A novel Fe3O4/ZnO/PANI/rGO nanohybrid material for radar wave absorbing

In this study, a novel RAM utilizing Fe3O4, ZnO, polyaniline (PANI), and reduced graphene oxide (rGO) in the form of nanohybrid is invented, namely Fe3O4/ZnO/PANI/rGO nanohybrid. In this study, the effects of the rGO fraction in Fe3O4/ZnO/PANI/rGO composition on the radar absorbing performance were investigated. Meanwhile, exploring the quality of the nanohybrid sample, such as the crystal structure, functional groups, morphology, magnetic properties, and reflection loss was also examined carefully. It shows that two crystalline phases of Fe3O4 and ZnO, as well as amorphous structures of PANI and rGO are formed independently, indicating successful nanohybrid formation. In this case, PANI functioned as a binder for Fe3O4 and ZnO, and thus, it could infiltrate the pores of rGO. Fe3O4/ZnO/PANI/rGO nanohybrid possesses superparamagnetic properties with decreasing saturation magnetization as rGO composition increases. Nevertheless, rGO enhanced the radar absorption performance with a maximum reflection loss of −8.57 dB at 11.10 GHz. In this present research, the synergy of combination between the magnetic and dielectric losses in the Fe3O4/ZnO/PANI/rGO nanohybrid is discussed together with plausible strategies to obtain highly efficient RAM.

A comparative DFT study of MgFe2O4 and MnFe2O4 spinel ferrites at various pressures to investigate the structural, mechanical, electronic, magnetic and optical properties for multifunctional applications

The structural, electronic, mechanical, optical, and magnetic properties of the MgFe2O4 and MnFe2O4 ferrites were investigated under pressures ranging from 0 to 20 GPa using the DFT-based CASTEP Code. XRD analyses indicated differences in lattice constants, volumes and d-spacing between these ferrites, with decreasing trends under applied pressure. The MgFe2O4 ferrite has lower X-ray density, but higher electronic bandgap energy compared to the MnFe2O4 ferrite, both showing semiconductor behavior. Magnetic properties show a decrease in total magnetic moment and saturation magnetization under applied pressure for both ferrites, making them potential materials for transformer and inductor cores. Mechanical properties confirm their stability, elastic behavior, ductility and ionic bond nature, suitable for electrochemical devices. The MgFe2O4 ferrite exhibits dominant absorption and optical conductivity in the visible region compared to the MnFe2O4 ferrite, making it a favorable choice for optoelectronic and photocatalytic applications.

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.