Electrospun Carbon Nanofibers Encapsulated with NiCoP: A Multifunctional Electrode for Supercapattery and Oxygen Reduction, Oxygen Evolution, and Hydrogen Evolution Reactions

Well-crystallized Cd-substituted Mn1-xCdxFe2O4 nanoparticles with x having values 0.0, 0.1 and 0.3 have been synthesized by hydrothermal route at 180oCwith the help ofNaOHasmineralizer. The as-prepared ferrite samples were characterized byXRD, SEMand vibrating samplemagnetometer (VSM). The XRD analysis showed that pure single phases of cubic ferrites were obtained with x up to 0.3. However, samples with x>0.3 form sodium cadmiumoxide (Na2CdO2) beside ferrite phase. The increase in the Cd-substitution up to x=0.3 increased the lattice parameter and the average crystallite size of the prepared ferrites. The saturation magnetization (Ms) increases with increase in Cd-substitution.

Hydrothermal synthesis and characterizations of Cd substituted Mn-ferrites

Ferrites belong to the wonder class of materials which are known for their wide application range. Among ferrites, spinel ferrites belong to the most promising soft magnetic materials with excellent properties like engineered band gap, high saturation magnetization, coercivity, and better thermal and electrical properties. Among spinel ferrites, Nickel ferrites: a soft, highly magnetic material that exhibit excellent electrical, magnetic, and optical characteristics. Nickel ferrites find their space in a variety of applications because of their unique properties when compared to other ferrite family members. These properties include high saturation magnetisation, less coercivity, high resistivity and permeability. In addition, nanometric Ni ferrites are unique in several properties with modified applications, such as high frequency applications, electronic devices with low loss, biomedical applications, and environmental remedial applications also. This review aim to explore possible synthesis routes, unique properties and diverse applications of Ni ferrite.

Recent advances on Nickel Nano-ferrite: A review on processing techniques, properties and diverse applications

Nanoferrites of Ni0.1Cu0.2MgxZn(0.7−x)Fe2O4 (x = 0.0, 0.15, 0.25, 0.35, 0.45, 0.55 and 0.70 wt%) system fabricated using flash auto combustion technique. All investigated samples annealed for 2 h at 600 °C. XRD, FTIR and TEM were utilized to evaluate the structural characterization of as-prepared samples. The electrical DC resistivity of the investigated samples is evaluated as a function of frequency and temperature. The initial magnetic permeability (μi) is dependent on the temperature and was measured at constant frequency 1 kHz and 10 kHz of the sinusoidal wave. A single-phase of spinel structure was formed and with increasing Mg content the peak (311) of 100% intensity decreases, which demonstrates the presence of Mg, which slows down the growth of the crystal as X-ray result. The FTIR spectra of the prepared ferrite samples are distinguished by the presence of two strong absorption bands (ν1 = 554 cm−1) and (ν2 = 449 cm−1). The morphological observation is determined by the transmission electron microscopy (TEM) and shows that the particles size ranged between 26 and 39 nm. It can notice shifted Curie temperature (Tc) to a higher temperature by increasing Mg content. Mass attenuation coefficient (μm), mean free path (λ), half value layer (X1/2), tenth value layer (X1/10) and effective atomic numbers (Zeff) for the studied samples, have been simulated using FLUKA (2020.0beta.2), while energy change from 15 × 10–3 to 153+ keV with increasing Mg concentration, both μm and Zeff decrease. The largest value of μm and Zeff when x = 0% while sample x = 0.35% has a minimum value of λ, X1/10 and X1/2.

Spectral, electrical, magnetic and radiation shielding studies of Mg-doped Ni–Cu–Zn nanoferrites

Nanocomposite films based on spinel ferrite (Mg0.8Zn0.2Fe1.5Al0.5O4) in a PVA matrix were obtained. An increase in the spinel concentration to 10 wt.% caused an avalanche-like rise in roughness due to the formation of nanoparticle agglomerates. The lateral mode of atomic force microscopy (AFM) allowed us to trace the agglomeration dynamics. An unexpected result was that the composite with 6 wt.% of filler had a low friction coefficient in comparison with similar composites due to the successfully combined effects of low roughness and surface energy. The friction coefficient decreased to 0.07 when the friction coefficient of pure PVA was 0.72. A specially developed method for measuring nano-objects’ surface energy using AFM made it possible to explain the anomalous nature of the change in tribological characteristics.

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Combined Effect of Microstructure, Surface Energy, and Adhesion Force on the Friction of PVA/Ferrite Spinel Nanocomposites

Soft-magnetic NiCoP coated hard-magnetic M-type ferrite BaFe12O19 (BaM)–polystyrene (PS) bilayer composite film was successfully synthesized. X-ray diffraction peaks exhibited no change in the structure of BaM after coating with PS. The NiCoP coated BaM–PS composite exhibited a wasp-waisted magnetic hysteretic loop with remarkable reduction in the coercivity, remanence and squareness with respect to BaM–PS, which is useful for the core of a magnetic switching device to control currents so large that they are unmanageable. Moreover, the initial permeability measurement exhibits initial permeability of around 100 000 and thermal stability up to 558 K, which is good for flux-amplifying components of smaller inductors.

https://google.iopscience.iop.org/article/10.1088/2053-1591/3/3/036104/pdf

Strong coercivity reduction and high initial permeability in NiCoP coated BaFe12O19–polystyrene bilayer composite

We reveal the potential effect of inclusion of M-type BaFe12
 O
 19 (BaM) particles in polystyrene (PS) polymer. BaM particles are attached rather well to a PS matrix with variable sizes and shapes. It demonstrated that the incorporation of BaM particles into a PS polymer would largely increase the initial magnetic permeability of BaM. Furthermore, it is significantly larger than corresponding values of commercially sintered MnZn ferrite. Therefore, BaM-PS composite imposes itself as a potential material in several applications such as flux amplifier and inductors.

Initial Magnetic Permeability of M-Type BaFe 12 O 19 -Polystyrene Composite

Brillouin function was modified to model the wasp-waisted magnetic hysteresis loop for soft-magnetic NiCoP-coated hard-magnetic M-type ferrite BaFe12O19 polystyrene (PS) bilayer composite film taking into account the effective applied magnetic field due to localized impurity phases and significant change in the azimuthal angle of the magnetic moment due to the formation of bilayer structure of film by the addition of PS. It is shown that there is a good fit to the experimental data observed in wasp-waisted magnetic hysteresis loop. The analysis shows that the forward magnetization and reversal process are typical.

Simulation of Wasp-Waisted Magnetic Hysteresis Loop for NiCoP-Coated BaFe12O19–Polystyrene Bilayer Composite Film

Low magnetic field magnetocaloric properties of Ni2+xMn1−xGe near phase transition from a ferromagnetic to a paramagnetic state were investigated theoretically for level of doping x = 0.1 and 0.2. It is shown that the change of Ni content allows the magnetocaloric effect in Ni2+xMn1−xGe to be tunable, which is more practical for construction magnetocaloric refrigeration. Furthermore, the results show that the magnetocaloric properties of Ni2+xMn1−xGe samples are significantly larger and comparable with some magnetocaloric properties of many materials like La1−xCdxMnO3, Gd1−xCaxBaCo2O5.5, Ge0.95Mn0.05, La1.25Sr0.75MnCoO6, Ni58Fe26Ga28, and MnAs films.

Nickle Concentration Effect on Low Magnetic Field Magnetocaloric Properties for Ni2+xMn1−xGe

M-type barium hexaferrite (BaM) particles–polystyrene (PS) composite has been successfully synthesized. Fourier transform infrared spectra confirm the synthesis of the BaM–PS composite. Scanning electron microscopy shows that BaM particles are attached rather well to the PS matrix and have variable sizes and shapes. Differential and thermogravimetric analysis indicate that PS chains are well coupled within the BaM powder and the thermal stability of PS is enhanced by incorporating BaM in the PS matrix.

https://iopscience.iop.org/article/10.1088/2053-1591/3/7/075302/pdf

Mahmoud A. Hamad

Papers

Strong coercivity reduction and high initial permeability in NiCoP coated BaFe12O19–polystyrene bilayer composite

Initial Magnetic Permeability of M-Type BaFe 12 O 19 -Polystyrene Composite

Simulation of Wasp-Waisted Magnetic Hysteresis Loop for NiCoP-Coated BaFe12O19–Polystyrene Bilayer Composite Film

Nickle Concentration Effect on Low Magnetic Field Magnetocaloric Properties for Ni2+xMn1−xGe

Improvement of the thermal properties of a polystyrene via inclusion of barium hexaferrite particles