A. A. Azab

To enhance the structure, optical band gap, and magnetic properties of CuO, the nanocomposites CuO/MFe ₂ O4 (where M = Co, Ni, and Fe) were synthesized using the sono-mechanical method. The structural study performed by X-ray diffraction technique evidenced that the monoclinic highly crystalline structure of CuO is formed with a reduction in particle size of CuO from 20.7 nm to < 20 nm in the nanocomposite. The optical analysis of the produced ferrite nanocomposites verified that the addition of (Ni, Fe, and Co) Fe2O4 to the CuO lattice resulted in a change in the optical energy band gap values from 1.52 eV for pure CuO nanoparticles to 1.46, 1.46, and 1.44 eV, respectively. Furthermore, the samples demonstrated superparamagnetic characteristics as appeared in the VSM technique, where milling the nanocomposite resulted in nearly negligible coercivity. Also, in VSM, it appeared that the incorporation of ferrite material to CuO improved its magnetic property, as the ferrites raised CuO’s saturation magnetization value.

In the current study, ZnO/NiFe₂O₄ nanocomposites were synthesized using co-precipitation and sono-mechanical methods, followed by annealing at temperatures of 200, 500, 800, and 1100 °C. We examined their structural, optical, and magnetic properties through XRD, TEM, UV-visible spectroscopy, and VSM. XRD analysis indicates that ZnO and NiFe₂O₄ exhibit hexagonal and cubic phases, respectively. Higher annealing temperatures led to increased ferrite peak intensity and larger crystallite sizes. The optical band gap (Eg) decreased, while saturation magnetization (Ms) increased with temperature; conversely, remanent magnetization (Mr) and coercivity (Hc) decreased. Observed color changes and optical/magnetic data suggested ion exchange between ZnO and NiFe₂O₄, resulting in Zn_1−xNixO and Ni_1−xZn_xFe₂O₄ formation. All findings demonstrated that an annealing temperature of 1100 °C significantly influenced the structural, optical, and magnetic properties. Optimizing the annealing temperature is essential for modifying the physical and optical properties of Zn/5% NFO nanocomposites for various applications.

It has been proven that alkali metals significantly influence the optical, electrical, and dielectric properties of transparent oxide. To that end, potassium (K) was employed as a substitutional dopant in the CdO matrix, and the influence of K on the structural, morphological, optical, and electrical properties was widely studied. Pure CdO and K-doped CdO nanoparticles (K = 0.0, 0.02, 0.04, and 0.06 mol) were synthesized via a facile co-precipitation method. XRD analysis indicated a cubic face center structure formed with the Fm3m (225) space group. A further establishment of the formation of CdO was recognized from CdO peaks in Fourier transform Infrared measurement(FTIR). The grain size declined with the increase in k concertation, as established by the size-strain method and HRTEM micrographs. HRTEM morphology investigation revealed the formation of nanoparticles adopting semi-hexagonal and spherical shapes. The UV–Vis-NIR spectra analysis exhibited K content played an important role in the optical parameters like reflectance, and band gap (E_g) CdO nanostructured. The obtained optical energy band gap was found to be increased due to potassium doping . The variation of dielectric properties of various CdO nanostructures with K doping concentrations was studied as a function of frequency and temperature and it was found to be enhanced with the inclusion of K. Finally, a small amount of potassium doping into CdO led to a significant varaiation in optical and the electrical properties, making it very effective in optoelectronic and electrical applications

Herein, the authors have explored the effect of incorporating TiO₂ (0.01, 0.05, and 0.1 wt%) into the PMMA network. The crystal structure of the pure and doped PMMA displayed amorphous to crystalline shift with a 17 nm for TiO₂ and 10 nm of PMMA/TiO₂ with the highest wt%. Maximum reflectance scopes 62% for PMMA/TiO₂ 0.1 wt% at 456 nm. The reduced bandgap from 4.2 for PMMA to 3.3 eV for PMMA/TiO₂ 0.1 wt% potentilally by the emergence of energy levels. Fourier transform infrared spectroscopy demonstrated the resembling spectroscopy without shifts in representative peaks except for the increase in the peak cited at 450 cm⁻¹, accredited to the Ti–O bond. The dielectric features verified the insertion of TiO₂ into PMMA matrix triggered the permittivity improvement, offering interfaces for the charges accumulation. The Antimicrobial specifications of the PMMA and PMMA/ TiO₂ were examined versus B. Subtilis, S. aureus, K. pneumoniae, E. coli, C. albicans, and A. niger. The advanced TiO₂ wt% the larger antimicrobial activity, particularly regarding gram-negative bacteria. Highest activity demonstrated 67.42% versus K. pneumoniae for PMMA/TiO₂ 0.1 wt%, although the antifungal activity against C. albicans and A. niger was inconsequential.

Pure CdS nanoparticles and Fe-doped CdS quantum dots (Cd_1−xFe_xS, where x = 0.0, 0.03, 0.06, 0.09, and 0.12) were successfully synthesized using the co-precipitation method. X-ray diffraction (XRD) analysis confirmed the cubic phase structure of CdS without additional peaks, indicating the effective incorporation of Fe ions into the CdS lattice. The crystallite size exhibited a gradual increase with increasing Fe content. High-resolution transmission electron microscopy (HR-TEM) revealed a well-defined spherical morphology for pure CdS, while Fe doping induced notable agglomeration in the quantum dots. X-ray photoelectron spectroscopy (XPS) confirmed the formation of the CdFeS composition and provided insights into the valence states of Cd, Fe, and S. UV–vis diffuse reflectance spectroscopy (DRS) demonstrated a decrease in the optical band gap from 2.29 eV to 2.18 eV with Fe doping, indicating a modification of the electronic structure. Magnetization studies revealed a transition from diamagnetic behavior in pure CdS to ferromagnetic behavior in Fe-doped samples. Additionally, Fe doping significantly influenced the magnetic parameters, including saturation magnetization, remanence, and coercivity. These results highlight the structural, optical, and magnetic properties of CdS can be tuned through Fe doping, making these materials promising candidates for optoelectronic and spintronic applications.

Hexaferrites SrAl_xFe_12−xO₁₉ (x = 0, 1, 2, 3, and 4) doped by Al³⁺ in an account of Fe³⁺ were synthesized using microwave digestion. X-ray diffraction pattern analysis revealed that the compound is polycrystalline with a hexagonal M-type structure of SrAl_xFe_12−xO₁₉ and P63/mmc space group is predominant for all dopants of Al³⁺ ion. The crystallite size of the SrAl_xFe_12−xO₁₉ phase has a maximum value for the un-doped sample (94.5 nm) and then decreases for all values of Al-doping. The SEM results showed that the average grain size increased with Al-doping till x = 2 and was almost stable. The magnetic properties were investigated by vibrating sample magnetometer. The results showed a continuous decrease in both saturation (Ms), and remnant (Mr), magnetization with Al-doping. At the same time, the coercive magnetic field, H_c, increases continuously with Al-doping except for x = 4, H_c slightly decreased. These results make these compound candidates to be used in data storage and magnetic memories. Dielectric properties investigation showed low-frequency dispersion in the dielectric results due to a space-charge effect. It has been demonstrated that enhancements in conductivity, dielectric constant (ε′), and dielectric loss (ε′′) rise with an increase in the concentration of Al³⁺ ions, suggesting that SrAl_xFe_12−xO₁₉ can be used for microwave absorption and other high-frequency applications.

In this work, the pristine ZnO, SrFe₁₂O₁₉ (SFO), and their nanocomposites (ZnO/x SFO: x = 1, 3 and 5%) were synthesized by co-precipitation and sonomechanical method. The x-ray diffraction data validate the preparation of ZnO, SFO, and nanocomposite samples with high phase purity. The optical band gap was calculated from UV–vis-NIR diffuse reflectance measurements, and it was modified by increasing SFO content. Adding 1, 3, and 5 wt% of SFO to the ZnO matrix showed ferromagnetic characteristics for the nanocomposites with a squareness ratio of around 0.49, which considered these nanocomposites as a magnetic semiconductor suitable for digital memory and spintronic applications. Additionally, the radiation shielding features of the prepared samples were evaluated. The shielding parameters for the studied samples were obtained using the Phy-X/PSD program. The fast neutron removal cross-section of SFO was 0.094 cm⁻¹, the highest among the investigated samples, while the composites had similar values, about 0.083 cm⁻¹. The results indicated that the γ--ray attenuation ability and the values of exposure buildup factor for the prepared samples were close. Therefore, ZnO, SFO, and their nanocomposites compared to stationary shielding materials (SMs), can be candidates for applications where radiation protection is needed.

The pure TiO₂ and TiO₂/xCoFe₂O₄ nanocomposites (0, 2, 4, and 6 wt. %) were synthesized using the sonomechanical method at room temperature. The prepared specimens were studied by scanning electron microscopy (SEM), energy-dispersive X-ray techniques (EDX), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and ac conductivity measurements. The sample exhibited homogeneous and well-distributed spherical nanoparticles of visible surface edges with average grain size ranging from 100 to 200 nm, as shown in the SEM micrograph. Raman spectra analysis showed the characteristic band for TiO₂ at 141.2, 233.08, 447.13, 609.55, and 639.4 cm⁻¹. The FTIR confirmed the interaction of CoFe₂O₄ and TiO₂ reflecting the successful formation of nanocomposites. Compared to pristine TiO₂, both the dielectric constant (ε') and conductivity were boosted by the inclusion of CoFe₂O₄. The behavior of the exponent factor (S) with temperature demonstrates that the conduction mechanism is the correlated barrier hopping (CBH) mechanism. The investigation of complex electric modulus established that the vertiginous nanocomposite had a non-Debye-type relaxation. The observed properties prove that TiO₂/ xCoFe₂O₄ (x = 0, 2, 4, and 6 wt. %) nanocomposites are very functional for electric storage applications.