مشروع البحث: MICROWAVE ABSORPTION PROPERTIES OF FERRITE-BASED NANOCOMPOSITES PREPARED FROM WASTE MATERIALS
| dc.contributor.advisor | جامعة ماليزيا | |
| dc.date.accessioned | 2024-12-25T11:21:02Z | |
| dc.date.available | 2024-12-25T11:21:02Z | |
| dc.description | The relative complex permittivity, ε' and ε′′ for Fe2-12h/ CNTs and Fe2-12h/ CNTs/GO samples is almost constant over the measurement frequency range (Figure 5.69 (a)). This is may be because when an electric field is applied, the polarization is virtually frequency-independent, which contributes to the independent oscillation of the electric dipole moments with the microwave frequencies (Zhu et al., 2017). Moreover, the real and imaginary parts of the complex magnetic permeability (μr = μ′ + iμ″) against the frequency of Fe2-12h/ CNTs and Fe2-12h/ CNTs/GO are shown in Figure 5.69 (b). In general, when a magnetic material is subjected to an external magnetic field with high frequency fluctuation, the amplitude of the magnetic induction intensity produced by the response lags behind the amplitude of the external magnetic field at a specific phase angle. Consequently, the material's permeability is variable. Therefore, in Figure 5.69 (d), the real (μ′) and imaginary parts (μ″) of pure Fe2-12h are larger than that of both Fe2-12h/CNTs and Fe2-12h/ CNTs/GO samples (Figure 5.69 (b)), this observed lower values of the relative magnetic permeability of Fe2-12h/CNTs and Fe2-12h/CNTs/GO is due to the non-magnetic behavior of the used CNTs and GO. There are some peaks of complex magnetic permeability (μr) of Fe2-12h/ CNTs and Fe2-12h/ CNTs/GO. Because the magnetic properties of Fe2-12h/ CNTs and Fe2-12h/ CNTs/GO at most originated from Fe2O3 ferrite. And because of the natural resonance and exchange resonance of Fe2O3 ferrite, the imaginary part of complex permeability exhibits some peaks, whereas the real part of the permeability exhibits a drop in the frequency range of 12–18 GHz. Additionally, the negative imaginary part of the complex magnetic permeability of Fe2 12h/ CNTs may be the result of the eddy current formed by the carriers under the influence of an alternating electric field, which is accompanied by an opposite-induced magnetic field, which produces a negative imaginary part of permeability. | |
| dc.description.abstract | μ′ and μ′′ values fluctuated with frequency. In the case of CNT/Ferrite composite, fluctuations in both μ' and μ'' values across the entire frequency range could be attributed to the variations in the distribution and arrangement of carbon nanotubes within the ferrite matrix can lead to fluctuations in magnetic properties, affecting both μ' and μ'' values. In addition, the presence of carbon nanotubes can indeed influence the magnetic domain dynamics within the ferrite material, leading to changes in domain wall movement, magnetic relaxation, or domain structure alterations. These changes can cause fluctuations in permeability values across different frequencies (Han and Deng, 2007; Sahu et al., 2018). The presence of carbon nanotubes at the interface with ferrite particles can lead to variations in magnetic behavior. Interfacial stress, strain, or magnetic coupling effects can cause fluctuations in permeability, particularly when exposed to different frequencies of electromagnetic fields (Al Khabouri et al., 2015). The real part of the permeability of the two samples is between 1.10 and 1.20 in the range of 8–12 GHz, which rises sharply in the range of 12–18 GHz. The imaginary part of the permeability also decreases with the increase in frequency and then tends to level off. On the one hand, an increase in the surface area enhances the exchange coupling reaction | |
| dc.identifier | 373 | |
| dc.identifier.uri | https://dspace.academy.edu.ly/handle/123456789/951 | |
| dc.subject | of the magnetic moment between particles; on the other hand, the addition of CNTs and | |
| dc.title | MICROWAVE ABSORPTION PROPERTIES OF FERRITE-BASED NANOCOMPOSITES PREPARED FROM WASTE MATERIALS | |
| dspace.entity.type | Project | |
| project.endDate | 2023 | |
| project.funder.name | قسم الفلسفة | |
| project.investigator | ELMAHAISHI MADIHA FATHI SALEM | |
| project.startDate | 2022 |