Structural Interpretation of Ion Transport and Small Polaron Hopping Conduction in Gd Substituted Nickel Nanoferrites

Sinha, A.; Dutta, Abhigyan

doi:10.1002/pssa.201700908

Cited by 11 publications

(8 citation statements)

References 43 publications

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“…Figures 11I(a)-(g) depicts the variation of DC conductivity of (100-x) ZnFe 2 O 4 /x NiO (x=0, 10, 20, 30, 40, 50, and 100 wt.%) NCs as the temperature increases from 303 to 573 K. It is clear that in all of the prepared samples the conductivity increases continuously, which reflects a semiconductor behavior. The conduction in the prepared samples is described by a hopping mechanism that is in turn due to the thermal energy supplied to the sample [56]. The hopping of electrons occurs between Fe 2+ and Fe 3+ ions manifesting n-type conduction, whereas the hole hopping occurs between Ni 2+ and Ni 3+ ions representing p-type conduction [57].…”

Section: Resultsmentioning

confidence: 99%

Synthesis and identification of structural, optical, electrical, and magnetic properties of novel ZnFe₂O₄/NiO nanocomposites

Aridi¹,

Awad²,

Khalaf³

2021

Phys. Scr.

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Novel nanocomposites (NCs) of (100-x) ZnFe 2 O 4 /x NiO (x=0,10,20,30,40,50, and 100 wt. %) NCs have been successfully synthesized by the two-step co-precipitation method. The XRD analysis showed the formation of both phases without any impurities. The FTIR spectroscopy provided characteristic vibrations of Zn-O, Fe-O, and Ni-O, which also confirmed the coexistence of both phases and the high purity of the samples. The TEM images revealed the rounded-cubes morphology of the nanocomposites with an average particle size ranging between 17 and 27 nm. The UV-vis spectroscopy showed that the absorbance edge of the synthesized NCs was slightly red-shifted with increasing NiO content. This indicates the narrowing of the optical bandgap due to the incorporation of sub-bandgap energy levels, triggered by the interface and surface defects. Furthermore, among all the nanocomposites, the nanocomposite with x=30 wt. % NiO exhibited the lowest PL emission intensity and possibly, the highest photocatalytic activity. The DC electrical conductivity was greatly enhanced with the addition of NiO to ZnFe 2 O 4 NPs for x30 wt. %. This increase may be due to the excessive charge accumulation on the various interfaces existing in the ZnFe 2 O 4 /NiO nanocomposites with increasing NiO content. Finally, the magnetic measurements displayed that ZnFe 2 O 4 /NiO NCs have superparamagnetic behavior with soft ferromagnetic of ferrites. The saturation magnetization (Ms) increased with increasing NiO content, which is useful for better magnetic recoverable photocatalyst. In addition, the δM-H plot showed stronger exchange coupling interaction between the magnetic phases in ZnFe 2 O 4 /NiO NCs.

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Section: Resultsmentioning

confidence: 99%

Synthesis and identification of structural, optical, electrical, and magnetic properties of novel ZnFe₂O₄/NiO nanocomposites

Aridi¹,

Awad²,

Khalaf³

2021

Phys. Scr.

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“…In view of the above, we have analyzed the temperature dependent dc conductivity of present samples using Mott variable range hopping (VRH) equation in the high temperature range (T300 K). The Mott VRH equation is expressed as [24,53,56,64]. The value of T 1 could be estimated by linear fitting to the data.…”

Section: Ac Conductivitymentioning

confidence: 99%

“…Here T 1 is the characteristic temperature coefficient which measures the degree of disorder. It is given as follows [24,53,56,64].…”

Section: Ac Conductivitymentioning

confidence: 99%

Electrical transport properties of nanocrystalline and bulk nickel ferrite using complex impedance spectroscopy: a comparative study

Paswan¹,

Pradhan²,

Kumar³

et al. 2022

Phys. Scr.

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In this work, the comparative study on the electrical transport properties of nanocrystalline nickel ferrite (NiFe2O4) and its bulk counterpart has been carried out in detail by using complex impedance spectroscopy in a wide range of frequencies (100 Hz-1MHz) and temperatures (40°C-320°C).The dispersive nature of the dielectric constant and loss factor is explained by the Maxwell-Wagner model and Koop’s phenomenological theory. The value of the dielectric constant for nanocrystalline nickel ferrite is found to be more as compared to its bulk counterpart. The frequency variation dielectric permittivity is well fitted with the modified Debye formula, which suggests the presence of multiple relaxation processes. The temperature dependent ac conductivity follows Jonscher’s universal power law and reveals the presence of multiple transport mechanisms from small polaron hopping (SPH) to correlated barrier hopping (CBH) mechanism near 200°C.The estimated values of Mott parameters are found to be satisfactory. Thermally activated relaxation phenomena have been confirmed by scaling curves of imaginary impedance (Z") and modulus (M"). The comparison between the Z" and M" spectra indicates that both long-range and short-range movement of charge carriers contribute to dielectric relaxation with short-range charge carriers predominating at low temperatures while long-range charge carriers are dominating at high temperatures. Analysis of the semicircular arcs of Nyquist plot indicates the presence of grain boundary contribution to the electrical conduction process for the nanocrystalline sample at high temperatures. The non-Debye type of relaxation has been examined by stretching exponential factor (β) which has been estimated by fitting the modified KWW (Kohlrausch-Williams-Watts) equation to the imaginary electric modulus curve. The value of β is found to be strongly temperature dependent and its value for the nanocrystalline sample is less than that of the bulk system which is explained on the basis of dipole-dipole interaction.

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“…Dielectric loss mainly consists of conductive loss and polarization loss, which can be represented by the Havriliak-Negami (HN) theory [54,55]. The dielectric loss of CNT/RGO/ZIF-8 composites intrinsically originate from conduction loss, interfacial polarization, and interfacial polarization loss.…”

Section: Resultsmentioning

confidence: 99%

Design of novel CNT/RGO/ZIF-8 ternary hybrid structure for lightweight and highly effective microwave absorption

Wang

Yang

et al. 2020

Nanotechnology

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Carbon-nanotube-based composites are highly desirable for addressing the difficulties relevant to the quality of electromagnetic wave absorbers. The introduction of lightweight nanocomposites for constructing new structures has been widely studied due to the transformation in impedance matching and attenuation. In this paper, a novel carbon nanotube-graphene oxide-zeolitic imidazolate framework-8 (CNT/RGO/ZIF-8) ternary hybrid structure was successfully fabricated by a facile solvothermal process. The ZIF-8 was entangled initially by carbon nanotubes via the π-π interaction between organic ligands and benzene ring structure in CNT. Then, the CNT/ZIF-8 composite was immobilized on the surface of RGO by interacting with the active functional group of RGO. The structure and performance for CNT, CNT/ZIF-8, and CNT/RGO/ZIF-8 were compared to investigate the interaction mechanisms between components, and CNT/ZIF-8 exhibited a distinct improvement for microwave absorption performance. Furthermore, the introduction of RGO can accelerate the amelioration of absorption characteristics. The interfacial bonding between CNT, RGO, and ZIF-8 exerts a great influence on the absorbing quality. The mechanism of absorption of electromagnetic waves was explained by the synergistic effects of conduction loss, polarization behaviors, and eddy current. The unique structure could offer new insights to exploit advanced microwave-absorption materials.

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Structural Interpretation of Ion Transport and Small Polaron Hopping Conduction in Gd Substituted Nickel Nanoferrites

Cited by 11 publications

References 43 publications

Synthesis and identification of structural, optical, electrical, and magnetic properties of novel ZnFe₂O₄/NiO nanocomposites

Synthesis and identification of structural, optical, electrical, and magnetic properties of novel ZnFe₂O₄/NiO nanocomposites

Electrical transport properties of nanocrystalline and bulk nickel ferrite using complex impedance spectroscopy: a comparative study

Design of novel CNT/RGO/ZIF-8 ternary hybrid structure for lightweight and highly effective microwave absorption

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Structural Interpretation of Ion Transport and Small Polaron Hopping Conduction in Gd Substituted Nickel Nanoferrites

Cited by 11 publications

References 43 publications

Synthesis and identification of structural, optical, electrical, and magnetic properties of novel ZnFe2O4/NiO nanocomposites

Synthesis and identification of structural, optical, electrical, and magnetic properties of novel ZnFe2O4/NiO nanocomposites

Electrical transport properties of nanocrystalline and bulk nickel ferrite using complex impedance spectroscopy: a comparative study

Design of novel CNT/RGO/ZIF-8 ternary hybrid structure for lightweight and highly effective microwave absorption

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Synthesis and identification of structural, optical, electrical, and magnetic properties of novel ZnFe₂O₄/NiO nanocomposites

Synthesis and identification of structural, optical, electrical, and magnetic properties of novel ZnFe₂O₄/NiO nanocomposites