“…No additional reflection peaks correspond to any secondary phase was observed in nanocrystalline Mn 1-x Zn x Fe 2 O 4 . The values of crystallite sizes are calculated using Scherrer's formula [ 49 ] and given in Table 1 . Fig.…”
Section: Resultsmentioning
confidence: 99%
“…The lattice constant values of nanocrystalline Mn 1-x Zn x Fe 2 O 4 are determined using the relation given in Ref. [ 49 ] and are given in Table 1 . The Zn substitution increases the values of the lattice constant gradually.…”
Section: Resultsmentioning
confidence: 99%
“…The obtained dried gel was heated continuously until self-combusted. The resultant ferrite powder was heat-treated for 1 h at 300 °C and then used for further characterization [ 28 , 49 ].…”
This paper reports the structural, morphological, spectroscopic, dielectric, ac conductivity, and impedance properties of nanocrystalline Mn
1-x
Zn
x
Fe
2
O
4
. The nanocrystalline Mn–Zn ferrites were synthesized using a solvent-free combustion reaction method. The structural analysis using X-ray diffraction (XRD) pattern reveals the single-phase of all the samples and the Rietveld refined XRD patterns confirmed the cubic-spinel structure. The calculated crystallite size values increase from 8.5 nm to 19.6 nm with the Zn concentration. The surface morphological analysis using field emission scanning electron microscopy and the transmission electron microscopy confirms the nano size of the prepared ferrites. X-ray photoelectron spectroscopy was used to study the ionic state of the atoms present in the samples. Further, the high-resolution Mn 2p, Zn 2p, Fe 2p, and O 1s spectra of Mn
1-x
Zn
x
Fe
2
O
4
does not result in the appearance of new peaks with Zn content, indicating that the Zn substitution does not change the ionic state of Mn, Zn, Fe, and O present in nanocrystalline Mn
1-x
Zn
x
Fe
2
O
4
. The investigated electrical properties show that the dielectric constant, tan δ and ac conductivity gradually decrease with increasing Zn substitution and the sample Mn
0
·
2
Zn
0
·
8
Fe
2
O
4
has the lowest value of conductivity at 303 K. The ac conductivity measured at different temperatures shows the semiconducting nature of the ferrites. The impedance spectra analysis shows that the contribution of grain boundary is higher compared with the grain to the resistance. The obtained results suggest that the Zn substituted manganese ferrite nanoparticles can act as a promising candidate for high-frequency electronic devices applications.
“…No additional reflection peaks correspond to any secondary phase was observed in nanocrystalline Mn 1-x Zn x Fe 2 O 4 . The values of crystallite sizes are calculated using Scherrer's formula [ 49 ] and given in Table 1 . Fig.…”
Section: Resultsmentioning
confidence: 99%
“…The lattice constant values of nanocrystalline Mn 1-x Zn x Fe 2 O 4 are determined using the relation given in Ref. [ 49 ] and are given in Table 1 . The Zn substitution increases the values of the lattice constant gradually.…”
Section: Resultsmentioning
confidence: 99%
“…The obtained dried gel was heated continuously until self-combusted. The resultant ferrite powder was heat-treated for 1 h at 300 °C and then used for further characterization [ 28 , 49 ].…”
This paper reports the structural, morphological, spectroscopic, dielectric, ac conductivity, and impedance properties of nanocrystalline Mn
1-x
Zn
x
Fe
2
O
4
. The nanocrystalline Mn–Zn ferrites were synthesized using a solvent-free combustion reaction method. The structural analysis using X-ray diffraction (XRD) pattern reveals the single-phase of all the samples and the Rietveld refined XRD patterns confirmed the cubic-spinel structure. The calculated crystallite size values increase from 8.5 nm to 19.6 nm with the Zn concentration. The surface morphological analysis using field emission scanning electron microscopy and the transmission electron microscopy confirms the nano size of the prepared ferrites. X-ray photoelectron spectroscopy was used to study the ionic state of the atoms present in the samples. Further, the high-resolution Mn 2p, Zn 2p, Fe 2p, and O 1s spectra of Mn
1-x
Zn
x
Fe
2
O
4
does not result in the appearance of new peaks with Zn content, indicating that the Zn substitution does not change the ionic state of Mn, Zn, Fe, and O present in nanocrystalline Mn
1-x
Zn
x
Fe
2
O
4
. The investigated electrical properties show that the dielectric constant, tan δ and ac conductivity gradually decrease with increasing Zn substitution and the sample Mn
0
·
2
Zn
0
·
8
Fe
2
O
4
has the lowest value of conductivity at 303 K. The ac conductivity measured at different temperatures shows the semiconducting nature of the ferrites. The impedance spectra analysis shows that the contribution of grain boundary is higher compared with the grain to the resistance. The obtained results suggest that the Zn substituted manganese ferrite nanoparticles can act as a promising candidate for high-frequency electronic devices applications.
“…For the semicircle in the high frequency range a capacitance C 1 of about 1.2-1.4 Â 10 À11 F is obtained, which is a typical value for the bulk material. 43,45 The second semicircle shows a capacitance of about 5 Â 10 À10 F. The second semicircle therefore can be attributed to the response of the grain boundaries, which show values between C 2 ¼ 10 À10 to 10 À8 F depending on the size of the grains in the particle, 46,52,53 i.e. with decreasing grain size the capacity shis to lower values resulting in an overlap of the bulk and grain boundary semicircle in nanocrystalline samples.…”
Section: View Article Onlinementioning
confidence: 97%
“…Each RQ element consists of a resistance R and a constant phase elements (CPE) Q representing one of the non-ideal semicircles. According to the brick layer model of microcrystalline ceramic materials, [43][44][45][46][47] the semicircle in the high frequency range is interpreted as the transport process inside the crystallites, i.e. the bulk properties, while the semicircle at lower frequencies represents the transport process across the grain boundaries.…”
Monophasic nano-crystalline CoFe 2 O 4 (CFO) nanoparticles of high purity have been synthesised through a low temperature hydrothermal route, which does not involve hazardous chemicals, or conditions. The easy, green procedure involves a hydrothermal treatment at 135 C of an aqueous suspension of the oxalate salts of the precursors. No further purification or annealing procedure was necessary to obtain the crystalline nano-structured oxide. The nanoparticles were characterized structurally and chemically by powder X-ray diffraction (PXRD), Inductively Coupled Plasma Spectrometry (ICP-MS) and Scanning Electron Microscopy (SEM), thus confirming the successful synthesis of the CoFe 2 O 4 particles with the expected crystal phase and stoichiometry and an almost complete inverse spinel structure. From the nanoparticles pellets were pressed to investigate the electronic conduction properties using electrochemical impedance spectroscopy (EIS). At low temperatures, the conductivity measurements reveal a semiconducting behavior originating from hopping between Co sites and a total conductivity dominated by the grain boundary contribution. At higher temperatures (T > 400 C) a metallic-insulator transition occurs, which is attributed to additional hopping of electrons between the Fe sites.
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