El. Abouzir

Bio: El. Abouzir is an academic researcher from Mohammed V University. The author has contributed to research in topics: Coercivity & Spinel. The author has an hindex of 1, co-authored 2 publications receiving 26 citations.

Magnetic and structural properties of single-phase Gd3+-substituted Co–Mg ferrite nanoparticles

Abstract: Nanocrystalline Gd3+-doped Co–Mg ferrite nanoparticles with the chemical formula Co0.7Mg0.3Fe(2−x)GdxO4 (x = 0.02) were prepared by coprecipitation for the first time. The properties of the nanoparticles were investigated by X-ray diffraction, confirming a single-phase, highly crystalline cubic spinel structure in the space group Fdm and an average crystallite size of 54 nm. The Fourier-transform infrared spectrum showed two fundamental absorption bands in the wavenumber range of 437–748 cm−1 attributed to the stretching vibration of tetrahedral and octahedral sites in the spinel structure. Scanning electron microscopy analysis showed that the nanoparticles are different in shape and slightly agglomerated. Energy-dispersive X-ray spectroscopy demonstrated the purity of the nano-ferrite powder. Magnetic measurements revealed ferrimagnetic behavior at room and low temperatures with high coercivity and a high saturation magnetization of 95.68 emu g−1, larger than that of pure bulk cobalt ferrite (80.8 emu g−1). Only ferrite cobalt synthesized sonochemically has been reported to have a higher saturation magnetization (92.5 emu g−1).

Novel magnetic nanomaterial Co0.7Zn0.3Fe2−xGdxO4 for nanotechnology applications: experimental and theoretical investigations

Abstract: Co0.7Zn0.3Fe2−xGdxO4 (x = 0.02) ferrite nanoparticles with average size of 32 nm is synthesized by the co-precipitation method for the first time. X-ray diffraction spectra revealed the formation of single-phase spinel with a high crystallinity. Fourier transform infra-red spectra confirmed the formation of spinel matrix crystallographic sites and Scanning Electron Microscopy images confirmed the formation of agglomerated spherical particles with nanometric sizes. The analysis of the magnetic properties indicates that the coercivity (Hc) and Curie temperature (Tc) values increase while the saturation magnetization (Ms) value decreases upon doping with Gd. These results can be seen as a significant improvement of the magnetic properties compared to the undoped material, which could be beneficial for nanotechnology applications. The material is also studied from a theoretical perspective using first-principles calculations. The used PBE-HF method based on the GGA method with the implication of the onsite-exact-exchange proved to be very accurate in describing the system, giving rise to a semi-conducting behavior for the inverse spinel CoFe2O4 and a metallic electronic structure for Gd-doped Co0.7Zn0.3Fe2O4.

Ni substitution effect on the structure, magnetization, resistivity and permeability of zinc ferrites

Abstract: Zn1−xNixFe2O4 ferrites up to x = 1.0 with Δx = 0.2 have been synthesized via solid state reactions and the sol–gel autocombustion technique with step-by-step co-firing. Data on the chemical composition and the surface morphology of the samples have been obtained using a scanning electron microscope. An X-ray powder diffractometer has been used to establish the phase purity and to determine the unit cell parameters. It has been found that the obtained samples had a spinel structure with the Fdm (No. 227) space group. The unit cell parameters decrease with increasing nickel concentration. The a unit cell parameter decreases almost linearly from ∼8.443 A for x = 0.0 down to ∼8.337 A for x = 1.0. The V unit cell volume decreases almost linearly from ∼601.72 A3 for x = 0.0 down to ∼579.52 A3 for x = 1.0. The magnetic characteristics of the obtained samples are determined and discussed. The Curie point of obtained samples varies in the range of 803.5–572.7 K. The maximum spontaneous magnetization of ∼74.6 emu g−1 at room temperature was fixed for the solid solution with x = 0.6. Ac-resistivity drops by more than 3 orders of magnitude in the frequency range 1–106 Hz. The composition with x = 0.6 has the minimum ac-resistivity of 5.3 kOm cm at a frequency of 106 Hz. The maximum value of the (μ′) real part of ∼11.2 and (μ′′) imaginary part of ∼5.2 of the permeability in the frequency range of 50 MHz–10 GHz is observed for the composition with x = 0.4. The composite samples for the microwave study were prepared by mixing of the ferrite powders with molten paraffin wax. The volume fraction of the ferrite filler in the composites was 25%. The largest value of the (μ′) real part of ∼3 and (μ′′) imaginary part of ∼0.63 of permeability is found for the x = 0.4 composite. The formation of the composite significantly reduces permeability.