A high-performance microwave absorption material is highly demanded. Herein, the laminated Ti
3
C
2
Mxene was synthesised via HF etching process, and the flaky carbonyl iron (FCI) particles were ...prepared by high-energy ball milling. The hybrid Ti
3
C
2
/FCI powders with different mass ratios were fabricated by ultrasonic mixing method. Electromagnetic and microwave absorption properties of the single layer Ti
3
C
2
/FCI coatings were investigated in 2–18 GHz. A broadened microwave absorption property can be realized by optimizing the Ti
3
C
2
and FCI content. Especially, the coating with 20 wt% Ti
3
C
2
and 40 wt% FCI loading presents the measured absorption bandwidth (RL < − 10 dB) of 8.16 GHz with the thickness of 1.0 mm. The remarkable microwave absorbing performance was attributed to the good impedance matching and moderate attenuation ability. These results indicate that the Ti
3
C
2
/FCI composites have great potential to be a broadband microwave absorbent.
An optimized NiZn ferrite absorber for the whole P-band (230 –1000 MHz) is proposed by inserting cross-shaped metamaterial. Effective absorption bandwidth below − 10 dB for the composite absorber ...covers the frequency range 210 MHz–1000 MHz. Electromagnetic wave attenuation mechanisms are revealed by surface current distribution and power loss density distribution. The increased absorption bandwidth of the composite absorber is attributed to the overlap effect of three absorption peaks originated from the multilayer cross-shaped metamaterial absorbers. Results indicate that the proposed composite absorber can be utilized in the P-band with relatively less thickness compared to the traditional NiZn ferrite absorber.
Multiferroic properties of La-modified four-layered perovskite Bi
5−
x
La
x
Fe
0.5
Co
0.5
Ti
3
O
15
(0 ≤
x
≤ 1) ceramics were investigated, by analyzing the magnetodielectric effect, ...magneto-polarization response and magnetoelectric conversion. X-ray diffraction indicated the formation of pure Aurivillius ceramics, and Raman spectroscopy revealed the Bi ions displacement and the crystal structure variation. The enhancement of ferromagnetic and ferroelectric properties was observed in Bi
5−
x
La
x
Fe
0.5
Co
0.5
Ti
3
O
15
after La modification. The evidence for enhanced ME coupling was determined by magnetic field-induced marked variations in the dielectric constant and polarization. A maximum ME coefficient of 1.15 mV/cm·Oe was achieved in Bi
4.25
La
0.75
Fe
0.5
Co
0.5
Ti
3
O
15
ceramic, which provides the possible promise for novel magnetoelectric device application.
Magnetic–dielectric composites are usually designed to develop high-performance microwave absorbers. In this paper, magnetic–dielectric Ti
3
SiC
2
/Co
2
Z ferrite composites were firstly prepared for ...application in microwave-absorbing materials. The phase structure, micro-morphology, electromagnetic response behavior, and microwave absorption performance of these composites have been investigated and subsequently discussed. The measured results showed that the introduction of dielectric Ti
3
SiC
2
into magnetic Co
2
Z ferrite can increase the complex permittivity and dielectric loss of these composites appropriately. And then, a desired stronger reflection loss peak of –38.04 dB could be achieved with a thin thickness of 1.5 mm in the Ti
3
SiC
2
/Co
2
Z composite-filled microwave-absorbing materials. It was also found that appropriately increasing the complex permittivity can improve the electromagnetic attenuation ability and the impedance-matching property simultaneously, which eventually contributes to the enhanced microwave absorption performance.
The corresponding mechanism of high complex permittivity for micro flaky Fe-filled composites was still not apparent. In this letter, the dielectric behaviors of flaky carbonyl iron/epoxy resin ...composites within 2–18 GHz were studied experimentally and theoretically. Results show that an obvious increase both in real and imaginary part of permittivity can be observed as the volume fractions of FCI is up to the percolation threshold. Considering the influence of conduction current, a revised Debye model of permittivity has been proposed to reveal the mechanism of dielectric behavior in composites. The best fitting result demonstrate that conduction loss played an important role in increasing the permittivity after percolation. Fe
3
O
4
was used as encapsulated shell on surface of the FCI to control the conduction and enhance the percolation threshold, resulting in better microwave absorption from better balance between the complex permittivity and permeability.
Magnetoelectric (ME) composites exhibiting strain-mediated coupling are gaining increasing interest for applications. In this paper, an enhancement of ME response on simple lead-free laminated ...composites (80Bi
0.5
Na
0.5
TiO
3
-20Bi
0.5
K
0.5
TiO
3
)/CoFe
2
O
4
(BNKT/CFO) prepared by a modified cofiring processing were demonstrated, by analyzing the effect of thickness variation on ME properties. The coexistence of independent BNKT and CFO phase and the presence of a clear and well-bonded interface were confirmed. Specifically, the maximum ME voltage coefficient of laminated composite reached up to 74.59 mV/(cm·Oe) with an optimized BNKT/CFO layer thickness ratio of 1:2. The static elastic model and the equivalent circuit model were used to determine the interface coupling. Also, there is a large magnetodielectric (MD) response up to 5.1% in a magnetic field of 8 kOe. Tuning the layer thickness, the ME response of laminated composite is further optimized, which is of significance in development of magnetic-field-tuned electronic devices.
The NiCuZn ferrites doped with Bi 2 O 3 and Co 2 O 3 were prepared by the solid-state reaction method. Micrographs were obtained by SEM. The complex permeability spectra were measured by Agilent ...E4991A and 16454A. Variation of the permeability under a magnetic field impulse was measured by Agilent 4284A. Effect of the Co 2 O 3 content on the permeability spectra of the NiCuZn ferrite samples before and after exposing to an impulse magnetic field was discussed. The corresponding permeability spectra of the samples were decomposed into the domain wall motion component and the spin rotation component. The results show that the permeability at 1 MHz decreases and the resonance frequency increases with more Co 2 O 3 content, and Co 2+ have different effect on the two kinds of magnetic susceptibility components. Different variation was revealed for the domain wall motion component and the spin rotation component after exposing to an impulse magnetic field. The decline rate of susceptibility by domain wall motion is smaller than that of susceptibility by spin rotation.
•Magnetic NiFe2O4-decorated Ti3C2 MXene were successfully synthesized.•Incorporation of NiFe2O4 enhance electromagnetic attenuation ability and impedance matching property.•A wide bandwidth of ...7.68 GHz was achieved in the NiFe2O4-Ti3C2 composite.
Incorporation of magnetic loss component is more favorable to high-performance microwave absorbing materials. In this paper, the NiFe2O4-decorated Ti3C2Tx MXene composites were synthesized by the in-situ chemical co-precipitation method. The magnetic NiFe2O4 nanoparticles were attached on the surfaces or inserted into the interlayers of Ti3C2Tx MXene. Interestingly, we reduced effectively complex permittivity and enhanced magnetic loss by increasing the NiFe2O4 content on Ti3C2Tx MXene. Stronger electromagnetic attenuation ability and preferable impedance matching property were achieved and considered to be responsible mainly for improving absorbing peaks as well as bandwidth of the NiFe2O4-Ti3C2Tx MXene composite. In particular, the NiFe2O4-Ti3C2Tx-20 sample exhibited an optimal effective absorption bandwidth (RL < −10 dB) of 7.68 GHz with the material thickness of only 1.5 mm. These findings are believed to pave the way of further promoting microwave absorption performance of Ti3C2Tx MXene from magnetic functionalized decoration of view.
Multiferroics with magnetic and ferroelectric ordering are considered as promising microwave absorption materials. Hence, the design and development of multiferroics are of great importance for ...microwave absorption field. Here we demonstrate an excellent microwave absorption in La-modified Aurivillius phase Bi
5
Co
0.5
Fe
0.5
Ti
3
O
15
multiferroics. The modified sample had layered perovskite structure and exhibited plate-like grains. The electromagnetic measurement suggested that the La substitution increase magnetic loss and improve impedance matching in Bi
5
Co
0.5
Fe
0.5
Ti
3
O
15
, which in turn contributed to the reflectivity and absorption bandwidth. Specifically, Bi
4.25
La
0.75
Ti
3
Fe
0.5
Co
0.5
O
15
has been found to deliver an absorption peak of − 15.8 dB at a small thickness of 1.8 mm with a broadened absorption bandwidth of 3.0 GHz, which is a promising incorporated microwave absorbent.
The effects of combinational additive on the DC-bias superposition characteristic of NiCuZn ferrite were investigated experimentally. The composite NiCuZn ferrite was prepared by a conventional ...ceramic method. The sharp decrease of the permeability can be avoided when the magnetic field is small. It is because the permeability is mainly attributed to the χspin with fine grain size. Owing to the thicker nonmagnetic grain boundary, samples with good DC-bias superposition characteristic can be obtained by special combinational additions. Composite addition of Bi2O3, AlBSi glass, and SnO2 can both retard the grain growth and increase the thickness of the nonmagnetic grain boundary δ. Finally, an excellent performance sample was obtained.
•We found that the decrease of permeability of mono-domain grains is much more slower under the DC-bias superposition magnetic field.•Good DC-bias superposition characteristic could be obtained by compound addition of Bi2O3, AlBSi glass and SnO2.•We gave a reasonable interpretation of the DC-bias superposition characteristic using the theory consisting of permeability.
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