Impedance spectroscopy of nanocrystalline MgFe2O4 and MnFe2O4 ferrite ceramics: Effect of grain boundaries on the electrical properties

Two ferrite ceramic materials, MgFe2O4 and MnFe2O4, were successfully fabricated by a conventional sintering of nanosized powders (at 1373 K for 2 h) synthesized by soft mechanochemical route. The particle size and morphology of powders were studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD analysis was carried out for the determination of phase purity, crystal structure and average crystallite size of sintered ferrites. Both mechanosynthesized ferrite samples show mean crystallite sizes in the nm-range. Over the frequency range of 100 Hz to 1 MHz, impedance spectra of prepared ferrite ceramics are investigated at and above room temperature. Changes in the impedance plane plots with temperature have been discussed and correlated to the microstructure of materials. An equivalent circuit model is applied to explore the electrical parameters (resistance and capacitance) associated with grains and grain boundaries. Complex impedance analysis indicates the dominance of grain boundary effects which control the overall electrical behaviour of studied ferrites. The decrease in grain boundary resistance with temperature suggests a thermally activated conduction mechanism.

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Grain boundary effects in NTC-PTC composite thermistor materials

Journal of Materials Research ◽

10.1557/jmr.1999.0019 ◽

1999 ◽

Vol 14 (1) ◽

pp. 120-123 ◽

Cited By ~ 10

Author(s):

D. J. Wang ◽

J. Qiu ◽

Y. C. Guo ◽

Z. L. Gui ◽

L. T. Li

Keyword(s):

Energy Level ◽

Grain Boundary ◽

Boundary Effect ◽

Complex Impedance ◽

Negative Temperature ◽

Impedance Analysis ◽

Composite Effect ◽

Complex Impedance Analysis ◽

Temperature Coefficient Of Resistivity ◽

Grain Boundary Effect

Yttrium-doped (Sr0.45Pb0.55)TiO3 ceramics have been studied by complex impedance analysis. As a sort of NTC-PTC composite thermistor, it exhibited a significantly large negative temperature coefficient of resistivity below Tc in addition to the ordinary PTC characteristics above Tc. It is found that the NTC effect in NTC-PTC materials was not originated from the deep energy level of donor (bulk behavior), but from the electrical behavior of the grain boundary. Therefore, the NTC-PTC composite effect was assumed to be a grain boundary effect, and yttrium was a donor at shallow energy level. The NTC-PTC ceramics were grain boundary controlled materials.

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The effects of calcination and doping on structural and dielectric properties of CaCu3-xCoxTi4O12 ceramic

Mediterranean Journal of Chemistry ◽

10.13171/10.13171/mjc8319052011nh ◽

2019 ◽

Vol 8 (3) ◽

pp. 234

Author(s):

Nasr Hadi ◽

Tajdine Lamcharfi ◽

Farid Abdi ◽

Nor-Said Echtoui ◽

Ahmed Harrach ◽

...

Keyword(s):

Dielectric Constant ◽

Dielectric Properties ◽

Complex Impedance ◽

Impedance Analysis ◽

Xrd Analysis ◽

Secondary Phases ◽

Solid State Method ◽

Complex Impedance Analysis ◽

Oxide Powders ◽

Increasing Temperature

The influences of calcination temperature and doping with cobalt in A–site on structural and dielectric properties of CaCu3-xCoxTi4O12 (CCCxTO, x = 0.00, 0.02 and 0.10) ceramics sintered at 1050 0C for 8h were investigated. The ceramic samples are prepared by the conventional solid-state method using high purity oxide powders, and they are calcined at 850 °C, 950 °C and 1050 0C for 4h. The X-ray diffraction (XRD) analysis of pure and doped CCTO samples calcined at 950 °C and 1050 0C showed no traces of any other secondary phases, while impurity phases alongside CCTO phase in the x=0.00 sample calcined at 850 0C was observed. Scanning electron microscopy (SEM) investigation showed an increase in grain size with increasing of Co content and calcining temperature. Dielectric measurements indicated that the dielectric constant of the pure CCTO calcined at 1050 0C/4h has a low value in the frequency range of 1kHz up to 1MHz, whereas the substitution of Co up to x = 0.10 into CCTO caused a huge increase in the dielectric constant value of the calcined samples which is equal to 153419 and 18957 at 950 °C and 1050 0C respectively. The complex impedance analysis of all samples shows a decrease in resistance with an increasing temperature, which suggests a semiconductor nature of the samples.

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Investigation on electrical conductivity and dielectric property of La0.8Pb0.2(Fe,Ti)0.5O3 ceramic nanoparticles

Journal of Advanced Dielectrics ◽

10.1142/s2010135x19500292 ◽

2019 ◽

Vol 09 (04) ◽

pp. 1950029

Author(s):

D. Triyono ◽

Y. Supriyadi ◽

H. Laysandra

Keyword(s):

Small Polaron ◽

Sol Gel ◽

Complex Impedance ◽

Impedance Analysis ◽

Ceramic Materials ◽

Ceramic Nanoparticles ◽

Complex Impedance Analysis ◽

Giant Dielectric ◽

Semiconductor Behavior ◽

Giant Dielectric Constant

The modification of the structure lanthanum orthoferrites (LaFeO[Formula: see text] to obtain ceramic materials with enhanced structural, optical, and electrical properties constitutes an active area of research. The preparation of La[Formula: see text]Pb[Formula: see text](Fe, Ti)[Formula: see text]O3 (LPFTO) ceramic nanoparticles by following a cation substitution approach from LaFeO3 using sol–gel and sintering methods is described. The electrical and dielectric properties of the obtained material are investigated. The contribution of grain and grain boundary in the conduction mechanism is demonstrated by complex impedance analysis. The LPFTO ceramic nanoparticles exhibit a giant dielectric constant of the order of 108. The conductivity analysis suggests the occurrence of thermally activated semiconductor behavior. Moreover, the ferromagnetic–paramagnetic semiconductor transition temperature is observed at 385[Formula: see text]K. The ac conductivity behavior satisfies the nonoverlapping small-polaron tunneling (NSPT) model.

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Dielectric, ferroelectrics properties and impedance spectroscopy analysis of the [(Na0.535K0.480)0.966Li0.058](Nb0.90Ta0.10)O3-based lead-free ceramics

Journal of Advanced Dielectrics ◽

10.1142/s2010135x15500071 ◽

2015 ◽

Vol 05 (01) ◽

pp. 1550007 ◽

Cited By ~ 2

Author(s):

M. Saidi ◽

A. Chaouchi ◽

S. D'Astorg ◽

M. Rguiti ◽

C. Courtois

Keyword(s):

Complex Impedance ◽

Negative Temperature ◽

Impedance Analysis ◽

Xrd Analysis ◽

Ac Impedance ◽

Nyquist Plot ◽

X Ray Diffraction ◽

Complex Impedance Analysis ◽

Lead Free Ceramics ◽

Different Temperatures

Polycrystalline of [( Na 0.535 K 0.480)0.966 Li 0.058] (Nb 0.90 Ta 0.10) O 3 samples were prepared using the high-temperature solid-state reaction technique. X-ray diffraction (XRD) analysis indicates the formation of a single-phase with orthorhombic structure. AC impedance plots were used as tool to analyze the electrical behavior of the sample as a function of frequency at different temperatures. The AC impedance studies revealed the presence of grain effect, from 425°C onwards. Complex impedance analysis indicated non-Debye type dielectric relaxation. The Nyquist plot showed the negative temperature coefficient of resistance (NTCR) characteristic of NKLNT. The AC conductivity results were used to correlate with the barrier hopping (CBH) model to evaluate the binding energy (Wm), the minimum hopping distance (R min ), the density of states at Fermi level (N(Ef)), and the activation energy of the compound.

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Effect of barium doping on electrical and electromechanical properties of (1-x)(Na0.5Bi0.5)TiO3-xBaTiO3

Mediterranean Journal of Chemistry ◽

10.13171/mjc8319050908mm ◽

2019 ◽

Vol 8 (3) ◽

pp. 198-208

Author(s):

Mohammed Mesrar ◽

Tajdine Lamcharfi ◽

Nor-Said Echatoui ◽

Farid Abdi ◽

Fatima Zahra Ahjyaje ◽

...

Keyword(s):

Dielectric Constant ◽

Complex Impedance ◽

Impedance Analysis ◽

Xrd Analysis ◽

Secondary Phases ◽

Solid State Method ◽

Complex Impedance Analysis ◽

Oxide Powders ◽

Increasing Temperature ◽

A Site

The influences of calcination temperature and doping with cobalt in A–site on structural and dielectric properties of CaCu3-xCoxTi4O12 (CCCxTO, x = 0.00, 0.02 and 0.10) ceramics sintered at 1050 0C for 8h were investigated. The ceramic samples are prepared by the conventional solid-state method using high purity oxide powders, and they are calcined at 850 °C, 950 °C and 1050 0C for 4h. The X-ray diffraction (XRD) analysis of pure and doped CCTO samples calcined at 950 °C and 1050 0C showed no traces of any other secondary phases, while impurity phases alongside CCTO phase in the x=0.00 sample calcined at 850 0C was observed. Scanning electron microscopy (SEM) investigation showed an increase in grain size with increasing of Co content and calcining temperature. Dielectric measurements indicated that the dielectric constant of the pure CCTO calcined at 1050 0C/4h has a low value in the frequency range of 1kHz up to 1MHz, whereas the substitution of Co up to x = 0.10 into CCTO caused a huge increase in the dielectric constant value of the calcined samples which is equal to 153419 and 18957 at 950 °C and 1050 0C respectively. The complex impedance analysis of all samples shows a decrease in resistance with an increasing temperature, which suggests a semiconductor nature of the samples

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Structural and Impedance Analysis of 0.7Pb(Mg1/3Nb2/3)O3- 0.3PbTiO3 Ceramic

Micro and Nanosystems ◽

10.2174/1876402913666210929125515 ◽

2021 ◽

Vol 13 ◽

Author(s):

Jayanta Kumar Mishra ◽

Khusboo Agrawal ◽

Banarji Behera

Keyword(s):

Electrical Properties ◽

Short Range ◽

Complex Impedance ◽

Relaxation Effect ◽

Impedance Analysis ◽

Xrd Analysis ◽

Nyquist Plot ◽

Space Group ◽

Complex Impedance Analysis ◽

Mobility Of Charge Carriers

Background: Since (1-x)[Pb(Mg1/3Nb2/3)O3]-(x)PbTiO3 (PMN-PT) ceramic has high dielectric constant and piezoelectric coefficient, it has been widely investigated for profound applications in electro-optical devices, sensors, multilayer capacitors and actuators. Objectives: The aim is to study the structural and electrical properties of 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (0.7PMN-0.3PT) ceramic to understand the biphasic structural nature using Rietveld Refinement. Also, it characterises on the basis of electrical properties such as impedance and modulus to understand the relaxation process, type of conduction process as well as the role of grain and grain boundary resistance in the material. Methods: 0.7PMN-0.3PT is synthesised by mixed oxide method using PbO, MgO, Nb2O5 and TiO2 as precursor materials. Results: The XRD data reveals the biphasic structure of tetragonal phase with the space group of P4mm and monoclinic phase with the space group of Pm. The complex impedance analysis clearly represents the effect of grain on the overall resistance and departs from normal Debye type behaviour. Also, the resistance is found to decrease with temperature, thereby confirming the semiconducting nature of the sample. The presence of long as well as short-range mobility of charge carriers is confirmed from the modulus and impedance analysis. The influence of long-range motion is observed at high temperature and of short-range motion at low temperatures. Conclusion: XRD analysis confirmed the biphasic structure of M+T phase. The frequency-dependent modulus and impedance spectroscopy show the presence of a relaxation effect in the ceramic which is found to increase with temperature. The Nyquist plot shows that the resistance is decreased with temperature, thereby confirming the NTCR behaviour in the studied sample.

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The effects of calcination and doping on structural and dielectric properties of CaCu3-xCoxTi4O12 ceramic

Mediterranean Journal of Chemistry ◽

10.13171/mjc8319052011nh ◽

2019 ◽

Vol 8 (3) ◽

pp. 234-244

Author(s):

Nasr Hadi ◽

Tajdine Lamcharfi ◽

Farid Abdi ◽

Nor-Said Echtoui ◽

Ahmed Harrach ◽

...

Keyword(s):

Dielectric Constant ◽

Dielectric Properties ◽

Complex Impedance ◽

Impedance Analysis ◽

Xrd Analysis ◽

Secondary Phases ◽

Solid State Method ◽

Complex Impedance Analysis ◽

Oxide Powders ◽

Increasing Temperature

The influences of calcination temperature and doping with cobalt in Aâ€“site on structural and dielectric properties of CaCu3-xCoxTi4O12 (CCCxTO, x = 0.00, 0.02 and 0.10) ceramics sintered at 1050 0C for 8h were investigated. The ceramic samples are prepared by the conventional solid-state method using high purity oxide powders, and they are calcined at 850 Â°C, 950 Â°C and 1050 0C for 4h. The X-ray diffraction (XRD) analysis of pure and doped CCTO samples calcined at 950 Â°C and 1050 0C showed no traces of any other secondary phases, while impurity phases alongside CCTO phase in the x=0.00 sample calcined at 850 0C was observed. Scanning electron microscopy (SEM) investigation showed an increase in grain size with increasing of Co content and calcining temperature. Dielectric measurements indicated that the dielectric constant of the pure CCTO calcined at 1050 0C/4h has a low value in the frequency range of 1kHz up to 1MHz, whereas the substitution of Co up to x = 0.10 into CCTO caused a huge increase in the dielectric constant value of the calcined samples which is equal to 153419 and 18957 at 950 Â°C and 1050 0C respectively. The complex impedance analysis of all samples shows a decrease in resistance with an increasing temperature, which suggests a semiconductor nature of the samples.

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Upshot of Concentration of Zirconium (IV) Oxynitrate Hexa Hydrate on Preparation and Analyses of Zirconium Oxide (ZrO2) Nanoparticles by Modified Co-Precipitation Method

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2021.19488 ◽

2021 ◽

Vol 21 (11) ◽

pp. 5707-5713

Author(s):

M. Ramachandran ◽

R. Subadevi ◽

P. Rajkumar ◽

R. Muthupradeepa ◽

R. Yuvakkumar ◽

...

Keyword(s):

Ionic Conductivity ◽

Complex Impedance ◽

Impedance Analysis ◽

Raw Material ◽

Precipitation Method ◽

Zro2 Nanoparticles ◽

Fixed Amount ◽

Complex Impedance Analysis ◽

Dta Analysis ◽

Co Precipitation

In the present work, pure nanocrystalline monoclinic Zirconia (ZrO2) has been successfully synthesized and optimized by the modified co-precipitation method. The concentration of raw material has been optimized with the fixed amount of precipitation agent (Potassium hydroxide KOH). The thermal history of the precursor has been examined through TG/DTA analysis. All the samples are subjected to study the structure, fingerprints of the molecular vibrations, and morphology analyses. The representative sample has been analyzed through Transmission Electron Microscope (TEM) and X-ray Photo Electron Spectroscopy (XPS) analyses. The as-prepared sample exhibits the better crystallinity and surface morphology with lesser particle size (190 nm) when the raw material concentration is 0.2 M. The as-prepared ZrO2 filler (0, 3, 6, 9, and 12 wt.%) is spread through the enhanced polymer electrolyte P(S-MMA) (27 Wt.%)-LiClO4 (8 wt.%)-EC + PC (1;1 of 65 wt.%) complex system via solution casting method. The as-synthesized electrolyte films are examined via complex impedance analysis. P(S-MMA) (27 wt.%)-LiCIO4 (8 wt.%)-EC + PC (1 ;1 of 65 wt.%)-6 wt.% of ZrO2 shows the high ionic conductivity 2.35 × 10–3 Scm–1. Temperature-dependent ionic conductivity studies obey the non-linear behavior. The enhanced ZrO2 has been expected to enhance the other electrochemical properties of the lithium secondary battery.

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