مشروع البحث: MICROWAVE ABSORPTION PROPERTIES OF FERRITE-BASED NANOCOMPOSITES PREPARED FROM WASTE MATERIALS
تحميل...
المساهمين
الممولين
رقم التعريف
373
الباحث
ELMAHAISHI MADIHA FATHI SALEM
الوصف
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.
الكلمات الدالة
of the magnetic moment between particles; on the other hand, the addition of CNTs and