Structural and Magnetic Properties of Nano Ferrite for Magnetoelectric Applications

Structure, Mössbauer, electrical, and γ-ray attenuation-properties of magnesium zinc ferrite synthesized co-precipitation method

For technical and radioprotection causes, it has become essential to find new trends of smart materials which used as protection from ionizing radiation. To overcome the undesirable properties in lead aprons and provide the proper or better shielding properties against ionizing radiation, the tendency is now going to use ferrite as a shielding material. The co-precipitation method was utilized to prevent any foreign phases in the investigated MZN nano-ferrite. X-ray diffraction (XRD) and Fourier transmission infrared spectroscopy (FTIR) methods were used to analyze the manufactured sample. As proven by XRD and FTIR, the studied materials have their unique spinel phase with cubic structure Fd3m space group. The DC resistivity of Mg-Zn ferrite was carried out in the temperature range (77-295 K), and its dependence on temperature indicates that there are different charge transport mechanisms. The Mössbauer spectra analysis confirmed that the ferrimagnetic to superparamagnetic phase transition behaviour depends on Zn concentration. The incorporation of Zn to MZF enhanced the nano-ferrite density, whereas the addition of different Zn-oxides reduced the density for nano-ferrite samples. This variation in density changed the radiation shielding results. The sample containing high Zn (MZF-0.5) gives us better results in radiation shielding properties at low gamma, so this sample is superior in shielding results for charged particles at low energy. Finally, the possibility to use MZN nano-ferrite with various content in different ionizing radiation shielding fields can be concluded.

Structure, Morphology and Electrical/Magnetic Properties of Ni-Mg Nano-Ferrites from a New Perspective

Using the auto combustion flash method, Ni1−x+2Mgx+2Fe2+3O4 (x = 0, 0.2, 0.6, 0.8 and 1) nano-ferrites were synthesized. All samples were thermally treated at 973 K for 3 h. The structural analysis for the synthesized samples was performed using XRD, high-resolution transmission electron microscopy (HRTEM), and FTIR. Scanning electron microscopy (SEM) was undertaken to explore the surface morphology of all the samples. The thermal stability of these samples was investigated using thermogravimetric analysis (TGA). XRD data show the presence of a single spinel phase for all the prepared samples. The intensity of the principal peak of the spinel phase decreases as Mg content increases, showing that Mg delays crystallinity. The Mg content raised the average grain size (D) from 0.084 μm to 0.1365 μm. TGA shows two stages of weight loss variation. The vibrating sample magnetometer (VSM) measurement shows that magnetic parameters, such as initial permeability (μ_i) and saturation magnetization (M_s), decay with rising Mg content. The permeability and magnetic anisotropy at different frequencies and temperatures were studied to show the samples’ magnetic behavior and determine the Curie temperature (T_C), which depends on the internal structure. The electrical resistivity behavior shows the semi-conductivity trend of the samples. Finally, the dielectric constant increases sharply at high temperatures, explained by the increased mobility of charge carriers, and decreases with increasing frequency.

TiO2-Doped Ni0.4Cu0.3Zn0.3Fe2O4 Nanoparticles for Enhanced Structural and Magnetic Properties

TiO2 (0-10 wt %)-doped nanocrystalline Ni0.4Cu0.3Zn0.3Fe2O4 (Ni-Cu-Zn) ferrites were synthesized using the sol-gel route of synthesis. The cubic spinel structure of the ferrites having the Fd3m space group was revealed from the analysis of Rietveld refined X-ray diffraction (XRD) data. The secondary phase of TiO2 with a space group of I41/amd was observed within the ferrites with doping, x > 3 wt %. The values of lattice parameter were enhanced with the addition of TiO2 up to 5 wt % and reduced further for the highest experimental doping of 10 wt %. Field emission scanning electron microscopy (FESEM) images exhibit the spherical shape of the synthesized particles with some agglomeration, while the compositional purity of prepared ferrite samples was confirmed by energy-dispersive X-ray spectroscopy (EDX) and elemental mapping. The cubic spinel structure of the prepared ferrite sample was confirmed by the Raman and Fourier transform infrared (FTIR) spectra. UV-visible diffuse reflectance spectroscopy was utilized to study the optical properties of the ferrites. The value of band gap energy for the pristine sample was less than those of the doped samples, and there was a decrement in band gap energy values with an increase in TiO2 doping, which specifies the semiconducting nature of prepared ferrite samples. A magnetic study performed by means of a vibrating sample magnetometer (VSM) demonstrates that the values of saturation magnetization of the ferrites decrease with the addition of TiO2 content, and all investigated ferrites show the characteristics of soft magnetic materials at room temperature. The Mössbauer study confirms the decrease in the magnetic behavior of the doped ferrites due to the nonmagnetic secondary phase of TiO2.