Multilayer Structures of a Zn0.5Ni0.5Fe2O4-Reduced Graphene Oxide/PVDF Nanocomposite for Tunable and Highly Efficient Microwave Absorbers

Amini, Majed; Kamkar, Milad; Rahmani, Farhad; Ghaffarkhah, Ahmadreza; Ahmadijokani, Farhad; Arjmand, Mohammad

doi:10.1021/acsaelm.1c00940

Cited by 50 publications

(52 citation statements)

References 66 publications

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“…where Z is the number of molecules in the unit cell (for the cubic spinel ferrite system, Z = 8), M is the molecular mass of the sample in gram/mole, V is the volume of the unit cell in cm 3 , and N o is the Avogadro's number (N o = 6.023 × 10 23 molecules/mole). In comparison with the parent compound, the molecular mass of NMFO is considerably lower but has a higher unit cell volume.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…Additionally, using intrinsic or doped NFO in multilayered structures or in conjunction with polymers has been proposed to design highly efficient EMI shielding materials. 3 For instance, the EMI absorber materials designed by means of a multilayer assembly of poly(vinylidene fluoride)-containing Zn-doped NFO have shown to increase the EMI shielding effectiveness dramatically. 3 The highest absorbance (>91%) was reported for a multilayer assembly with a tailored composition and layering sequence.…”

Section: ■ Introductionmentioning

confidence: 99%

“…3 For instance, the EMI absorber materials designed by means of a multilayer assembly of poly(vinylidene fluoride)-containing Zn-doped NFO have shown to increase the EMI shielding effectiveness dramatically. 3 The highest absorbance (>91%) was reported for a multilayer assembly with a tailored composition and layering sequence. 3 Therefore, understanding the electrical, magnetic, and dielectric properties of intrinsic and doped NFO nanomaterials warrants further investigations.…”

Section: ■ Introductionmentioning

confidence: 99%

“…3 The highest absorbance (>91%) was reported for a multilayer assembly with a tailored composition and layering sequence. 3 Therefore, understanding the electrical, magnetic, and dielectric properties of intrinsic and doped NFO nanomaterials warrants further investigations. Furthermore, compared to bulk materials, transition-metalbased engineered nanostructured materials are expected to provide excellent opportunities to tailor and/or manipulate the quantum effects and thereby derive novel electrical, optical, and magnetic properties.…”

Section: ■ Introductionmentioning

confidence: 99%

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Tunable Dielectric Properties of Nickel Ferrite Derived via Crystallographic Site Preferential Cation Substitution

et al. 2022

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We report on the tunable dielectric properties achieved in cation-substituted nickel ferrite (NiFe 2 O 4 ; NFO) by selectively engineering the crystallographic site occupation of the dopant cation in the NFO ceramics. The NFO, Mg-substituted NFO (NiMg 0.2 Fe 1.8 O 4 ; NMFO), and In-substituted NFO (NiIn 0.2 Fe 1.8 O 4 ; NIFO) nanocrystals were synthesized by employing a tartrate-gel chemical route, followed by calcination at 500 °C. High-resolution transmission electron microscopy (HRTEM) analyses indicate the crystal quality of NFO, NMFO, and NIFO nanomaterials. The HRTEM data revealed that all of the ferrite materials were nanocrystalline with sizes in the range of 15−25 nm. Coupled with HRTEM analyses, X-ray diffraction analyses indicate the formation of single-phase spinel-structured NFO, NMFO, and NIFO materials without any detectable impurities. Chemical analysis performed using Mossbauer spectroscopy indicates that Mg 2+ occupies the octahedral site, while In 3+ preferably occupies the tetrahedral site of the spinel-structured NFO. The Fourier transform infrared (FTIR) absorption bands corresponding to metal−oxygen (M−O) intrinsic stretching vibration in the octahedral unit (MO 6 ) and the tetrahedral unit (MO 4 ), respectively, were noted in all of the samples. However, the trend in the frequency shift of these bands in Mg-and In-substituted NFO materials is different due to the occupation of different sites of Mg and In as confirmed by Mossbauer studies. The electronic structure and chemical valence state analysis using X-ray photoelectron spectroscopy (XPS) corroborates with chemical bonding analyses performed by FTIR and cation distribution evaluation carried out by Mossbauer spectroscopy. The energy-dispersive X-ray spectrometry (EDS) data, in addition to XPS and FTIR analyses, further validate the formation of uniform and chemically homogeneous samples. The corresponding cation distribution revealed from Mossbauer studies correlates with the variation of dielectric properties of the doped NFO samples with respect to intrinsic NFO. At room temperature, the dielectric constant (ε) of NFO and NMFO is found to be nearly the same and constant over a wide range of frequencies. However, in NIFO, ε decreases with the applied frequency. The differences are attributed to the size effect and site preference of dopants (Mg 2+ and In 3+ ). Irrespective of the dopants, an increase in the temperature enhances the dielectric constant, which is due to an increase in the number of free charge carriers. A thermally activated electrical conduction mechanism was operative in NFO, NMFO, and NIFO materials. The activation energies for NFO, NFMO, and NIFO were 18.84, 34.48, and 57.14 meV, respectively. The enhanced dipolar effect of In 3+ at the tetrahedral site compared to Mg 2+ at the octahedral site may be the origin of the relatively higher value of activation energy in NIFO compared to intrinsic and Mg-substituted NFO.

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Section: ■ Materials and Methodsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Tunable Dielectric Properties of Nickel Ferrite Derived via Crystallographic Site Preferential Cation Substitution

et al. 2022

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“…As can be seen in Figure 4g, the dominant mechanism of shielding is absorption, i.e., absorbance ( A ) > reflectance ( R ), in the probed frequency window, making our aerogels a wave absorber, a versatile candidate for medical and military applications. [ 59 ] Indeed, due to the low density of the shields, the EM waves can penetrate the structure. Then, the penetrated waves will be trapped by the primary and secondary pores via wave scattering and multiple reflections at the abundant solid–air interfaces, leading to prolonging the trajectory and, thus, dissipation of the EM waves.…”

Section: Resultsmentioning

confidence: 99%

Structured Ultra‐Flyweight Aerogels by Interfacial Complexation: Self‐Assembly Enabling Multiscale Designs

Kamkar

Ghaffarkhah

Ajdary

et al. 2022

Small

Self Cite

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The rapid co‐assembly of graphene oxide (GO) nanosheets and a surfactant at the oil/water (O/W) interface is harnessed to develop a new class of soft materials comprising continuous, multilayer, interpenetrated, and tubular structures. The process uses a microfluidic approach that enables interfacial complexation of two‐phase systems, herein, termed as “liquid streaming” (LS). LS is demonstrated as a general method to design multifunctional soft materials of specific hierarchical order and morphology, conveniently controlled by the nature of the oil phase and extrusion's injection pressure, print‐head speed, and nozzle diameter. The as‐obtained LS systems can be readily converted into ultra‐flyweight aerogels displaying worm‐like morphologies with multiscale porosities (micro‐ and macro‐scaled). The presence of reduced GO nanosheets in such large surface area systems renders materials with outstanding mechanical compressibility and tailorable electrical activity. This platform for engineering soft materials and solid constructs opens up new horizons toward advanced functionality and tunability, as demonstrated here for ultralight printed conductive circuits and electromagnetic interference shields.

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Tunable Electromagnetic Performance of Pt–Si–O Films in Mid‐Infrared and Microwave Spectrums

Luo,

Fan,

et al. 2024

Adv Eng Mater

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Electromagnetic performance regulation in mid‐infrared (MIR) and microwave (MW) spectrums is crucially significant, which can be achieved by heterophase introduction and structural manufacturing. In this work, Si‐O amorphous phase is introduced into Pt film by magnetron co‐sputtering technique, the film thickness is optimized by adjusting deposition time. After annealing treatment, a double‐layered structure is constructed with the migration and growth of Pt crystals, in which the lower layer is composed of Pt coarse grains while the upper layer is Si‐O amorphous phase with embedded Pt fine grains. Furthermore, due to the thickness difference, diverse kinds of structural patterns (arrays or mesh) can be obtained with the solid‐state dewetting of the lower layer. According to the increasing thickness, the infrared emissivity can decrease from 0.67 to 0.25 (8–14 μm), demonstrating a great decline of apparent temperature of 162.9 °C when the background is 300 °C. And the microwave transmissivity also exhibits tremendous variation over 90% (from 96% to 5%), realizing the transformation from transmitting to shielding.

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Multilayer Structures of a Zn_0.5Ni_0.5Fe₂O₄-Reduced Graphene Oxide/PVDF Nanocomposite for Tunable and Highly Efficient Microwave Absorbers

Cited by 50 publications

References 66 publications

Tunable Dielectric Properties of Nickel Ferrite Derived via Crystallographic Site Preferential Cation Substitution

Tunable Dielectric Properties of Nickel Ferrite Derived via Crystallographic Site Preferential Cation Substitution

Structured Ultra‐Flyweight Aerogels by Interfacial Complexation: Self‐Assembly Enabling Multiscale Designs

Tunable Electromagnetic Performance of Pt–Si–O Films in Mid‐Infrared and Microwave Spectrums

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