scholarly journals Conduction Mechanism by Using CBH Model in Fe3+ and Mn3+ Ion Modified Pb(Zr0.65−xAxTi0.35)O3 (A = Mn3+/Fe3+) Ceramics

2013 ◽  
Vol 2013 ◽  
pp. 1-10
Author(s):  
Niranjan Sahu ◽  
S. Panigrahi ◽  
Manoranjan Kar
Keyword(s):  
Ac Conductivity ◽  
Conduction Mechanism ◽  
Rietveld Method ◽  
Compositional Analysis ◽  
Energy Dispersive Spectrum ◽  
Ion Concentration ◽  
Present Sample ◽  
Cbh Model ◽  
Dielectric Constant And Loss ◽  
Xrd Patterns

Polycrystalline samples of manganese and iron substituted lead zirconium titanate (PZT) with general formula Pb(Zr0.65−xAxTi0.35)O3 (A = Mn3+ and Fe3+) ceramics have been synthesized by high temperature solid state reaction technique. X-ray diffraction (XRD) patterns were recorded at room temperature to study the crystal structure. All the patterns could be refined by employing the Rietveld method to R3c space group with rhombohedral symmetry. Microstructural properties of the materials were analyzed by scanning electron microscope (SEM), and compositional analysis was carried out by energy dispersive spectrum (EDS) measurements. All the materials exhibit ferroelectric to paraelectric transition. The variation of dielectric constant and loss tangent with temperature and frequency is investigated. The decrease of activation energy and increases of AC conductivity with the Fe3+ or Mn3+ ion concentration have been observed. The AC conductivity has been analyzed by the power law. The frequency exponent with the function of temperature has been analyzed by assuming that the AC conduction mechanism is the correlated barrier hopping (CBH) model. The conduction in the present sample is found to be of bipolaron type for Mn3+ ion-doped sample. However, the conduction mechanism could not be explained by CBH model for Fe3+ ion-doped sample.

scholarly journals Influence of BaO Doping on the Structural, ac Conductivity, and Dielectric Properties of BiFeO3 Multiferroic Nanoparticles

2021 ◽  
Author(s):  
M. S. Ayoub ◽  
Ibrahim Morad ◽  
H. Elhosiny Ali ◽  
M. M. Mostafa ◽  
M. M. El–Desoky
Keyword(s):  
Curie Temperature ◽  
Ac Conductivity ◽  
Conduction Mechanism ◽  
Fourier Transforms ◽  
Information Storage ◽  
X Ray Diffraction ◽  
Cbh Model ◽  
Storage Devices ◽  
Electrical Conductivities ◽  
Xrd Patterns

Abstract The Bi1 − xBaxFeO3 (BiBaFeO3) multiferroic nanoparticles with different Ba molar concentrations were fabricated in reliance on the solid-state reaction technique. Nanostructures of the prepared samples were confirmed by X-ray diffraction (XRD) together with Fourier transforms infrared (FTIR) spectroscopy, whereas the ac conductivity, dielectric and ferroelectric features were examined depending on the RLC Bridge, and Sawyer–Tower circuit. XRD patterns displayed the creation of rhombohedral–hexagonal single-phase of BiBaFeO3. The formation of BiBaFeO3 multiferroic nanoparticles was confirmed by FTIR spectra. Curie temperature (TC) was observed around 1121–1189 K. Ferroelectric polarization was enhanced with remnant polarization of 88.8 µC/cm2 by Ba2+ ions substitution at x = 0.15 mol%. Besides, ac electrical conductivities as a function of frequency as well as temperature were reported for all BiBaFeO3 multiferroic nanoparticles, which exhibit a strong frequency dependence with conduction mechanism is the correlated barrier hopping (CBH) model. The obtained high polarization and Curie temperature enhance their use in information storage devices.

AC CONDUCTION PHENOMENON OF Li2O–WO3–B2O3 GLASSES DOPED WITH V2O5

2013 ◽  
Vol 06 (03) ◽  
pp. 1350032 ◽  
Author(s):  
LINGANABOINA SRINIVASA RAO ◽  
NALLURI VEERAIAH ◽  
TUMU VENKATAPPA RAO
Keyword(s):  
High Temperatures ◽  
Ac Conductivity ◽  
Conduction Mechanism ◽  
Glass Composition ◽  
Melt Quenching ◽  
Frequency Exponent ◽  
Spreading Factor ◽  
Cbh Model ◽  
Tan Δ ◽  
Ac Conduction

The glass composition 40 Li 2 O –5 WO 3–(55−x) B 2 O 3: x V 2 O 5 for x = 0.2, 0.4, 0.6 and 0.8 is chosen for the present study. The glass samples were synthesized by conventional melt-quenching technique. The dielectric properties such as constant (ε′), loss (tan δ) and ac conductivity (σac) are carried out as a function of temperature (30–270°C) and frequency (102–105 Hz). The glass sample (at x = 0.6) exhibited highest ac conductivity (σac) and spreading factor (β) among all the samples. All glasses exhibited mixed conduction (both electronic and ionic) at high temperatures. The frequency exponent s denotes the ac conduction mechanism is associated with both QMT model (at low temperatures) and CBH model (at high temperatures).

AC conductivity and conduction mechanism study of rubidium gadolinium diphosphate compound

2018 ◽  
Vol 93 (5) ◽  
pp. 603-610 ◽  
Author(s):  
Samia Mathlouthi ◽  
Abderrazek Oueslati ◽  
Bassem Louati
Keyword(s):  
Ac Conductivity ◽  
Conduction Mechanism ◽  
Mechanism Study

Thermodynamic properties and application of CBH model in the ac conductivity of LiNi1.5P2O7 ceramic

Ionics ◽  
2014 ◽  
Vol 20 (8) ◽  
pp. 1071-1078 ◽  
Author(s):  
R. Ben Said ◽  
B. Louati ◽  
K. Guidara ◽  
S. Kamoun
Keyword(s):  
Thermodynamic Properties ◽  
Ac Conductivity ◽  
Cbh Model

scholarly journals Modification of structural and dielectric properties of polycrystalline Gd-doped BFO–PZO

2018 ◽  
Vol 08 (05) ◽  
pp. 1850031 ◽  
Author(s):  
Ambika Ray ◽  
Banarji Behera ◽  
Tanmoy Basu ◽  
Saumitra Vajandar ◽  
Santosh Kumar Satpathy ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Boundary Effect ◽  
Ion Beam ◽  
Ferroelectric Properties ◽  
Compositional Analysis ◽  
Structural Defects ◽  
X Ray ◽  
Dielectric Constant And Loss ◽  
Before And After ◽  
Lcr Meter

[Formula: see text](BiFe[Formula: see text]GdxO3)–y(PbZrO3) composites [Formula: see text], having four different Gd concentrations ([Formula: see text], 0.1, 0.15, and 0.2), were synthesized and their structural, dielectric, and ferroelectric properties have been studied using different characterization techniques. In addition, to investigate the effect of ion implantation on the microstructure and dielectric properties, these composites were exposed to 2[Formula: see text]MeV He[Formula: see text]-ions. Modifications of the structure, surface morphology and electrical properties of the samples before and after ion exposure were demonstrated using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) technique, and LCR meter. The compositional analysis was carried out using energy dispersive X-ray spectrometry (EDS). XRD results demonstrated a decrease in the intensity profile of the dominant peak by a factor of 6 showing a degradation of the crystallinity. Willliamson–Hall (WH) plots reveal reduction in the grain size after irradiation along with an increase in strain and dislocation density. A decrease in the dielectric constant and loss has been recorded after ion beam exposure with reduction in ac conductivity value. The contribution of grain and grain boundary effect in conduction mechanism has been addressed using Nyquist plots. All the samples demonstrate a lossy ferroelectric loop which shows a clear modification upon irradiation. The role of structural defects modifying the physical properties of the composite materials is discussed in this work.

The Effects of Nickel Doping on the Structure of LiNixFe1-xPO4/C Cathode Material

2019 ◽  
Vol 964 ◽  
pp. 45-49 ◽  
Author(s):  
Purnama Sari Suci ◽  
Mochamad Zainuri ◽  
E. Endarko
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Rietveld Method ◽  
Solid State Reaction Method ◽  
Natural Material ◽  
Second Phase ◽  
Nickel Doping ◽  
X Ray ◽  
Xrd Patterns ◽  
Olivine Structure

This study has been successfully synthesized Nickel (Ni)-doped olivine-type LiNixFe1-xPO4/C with x= 0, 0.01, 0.02, 0.03 as cathode materials, using the solid-state reaction method was in order to investigate the effect on the structure and morphology. The precursor material of ion Ferro (Fe) is used natural material from ironstone of Tanah Laut Kalimantan Indonesian which combined with proanalis materials. The X-Ray Diffraction (XRD) patterns on the structure magnetite iron have shown that single phase of Fe3O4 and the patterns of structure LiNixFe1-xPO4/C indicated that doping Ni2+ have shown the orthorhombic structure with space group Pnma for all LiNixFe1-xPO4/C samples. Base on Rietveld method by Rietica software, the formation of phase resulted in olivine structure except at the concentration x = 0.02 and 0.03 have a second phase, that is nasicon structure with a smaller percentage than olivine structure. The general condition, coating carbon on LiNixFe1-xPO4/C particles by solid state reaction can be perfect which demonstrate the homogeneous existence of carbon on the surface of LiNixFe1-xPO4/C particles shown by images Scanning Electron Microscopy (SEM). The increased doping of Ni ions causing the Fe ions to decrease base on Energy Dispersive X-Ray Spectroscopy (EDS) observations.

Investigations on the Structural, Optical and Dielectric Properties of Ball-Milled ZnO–Fe2O3 Nanocomposites

2020 ◽  
Vol 19 (04) ◽  
pp. 1950034
Author(s):  
V. Balachandar ◽  
J. Brijitta ◽  
K. Viswanathan ◽  
R. Sampathkumar
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Ball Milling ◽  
High Energy ◽  
X Ray Diffraction ◽  
Dielectric Constant And Loss ◽  
Energy Ball ◽  
Uv Visible ◽  
Ball Milling Technique ◽  
Xrd Patterns

In this study, ZnO–Fe2O3 nanocomposites were prepared by high-energy ball milling technique and characterized through X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), UV–visible spectroscopy and dielectric spectroscopy. The amount of Fe2O3 in the ZnO–Fe2O3 nanocomposites was varied at the rates of 1[Formula: see text]wt.%, 3[Formula: see text]wt.% and 5[Formula: see text]wt.% in order to investigate its influence on the structural, optical and dielectric properties of the nanocomposites. XRD patterns of nanocomposites revealed no shift in peak positions and hence confirmed the formation of composites after ball milling. Further, it was observed from FESEM analysis that Fe2O3 particles were distributed randomly on the ZnO matrix of the nanocomposites. ZnO–Fe2O3 nanocomposites reveal extended optical absorption in the range of 400–600[Formula: see text]nm from UV studies. The dielectric constant and loss of the nanocomposites decrease exponentially with increase in frequency. The composition and frequency dependences of the dielectric constant, dielectric loss and AC conductivity are explained based on the Maxwell–Wagner effect and Koop’s theory.

Electric and dielectric properties of CdSO4-doped borate glasses

2019 ◽  
Vol 33 (04) ◽  
pp. 1950011 ◽  
Author(s):  
E. M. Ahmed
Keyword(s):  
Ac Conductivity ◽  
Thermal Activation ◽  
Relaxation Times ◽  
Wide Distribution ◽  
Ion Density ◽  
Cbh Model ◽  
Oxygen Ion ◽  
Dielectric Data ◽  
Quenching Method ◽  
Loss Formula

A system of (100-x)B2O3⋅xCdSO4glasses (0 [Formula: see text]x [Formula: see text] 40) is set by the ordinary quenching method. Density ([Formula: see text]), molar volume (V[Formula: see text]) and oxygen ion density (N[Formula: see text]) are found to increase with the increase of CdSO4in the samples. The dc conductivity ([Formula: see text]) and the ac conductivity ([Formula: see text]) are measured in the temperature range from 308 to 735 K. [Formula: see text] is found to follow the thermal activation Arrhenius relation with activation energies between 0.36 and 0.76 eV. Ac conductivity and the exponent factor (s) confirm that the CBH model is the origin of the conduction. The dielectric constant ([Formula: see text]) and loss ([Formula: see text]) are studied as a function of the temperature and frequency. The dielectric data are fitted according to the Cole–Cole equations. The values of [Formula: see text] parameter are found to vary between 0.2 and 0.58 which means that these glasses exhibit a wide distribution of relaxation times.

THE EFFECT OF OPERATING CONDITIONS ON THE SPARK GENERATED AU-PD NANOPARTICLES

2012 ◽  
Vol 05 ◽  
pp. 291-298 ◽  
Author(s):  
N. S. Tabrizi ◽  
A. Schmidt-Ott
Keyword(s):  
Inductively Coupled Plasma ◽  
Bimetallic Nanoparticles ◽  
Compositional Analysis ◽  
Pd Nanoparticles ◽  
Operating Conditions ◽  
X Ray Diffraction ◽  
Conductive Materials ◽  
Inductively Coupled ◽  
Xrd Patterns ◽  
Spark Energy

Spark discharge is a technique for producing nanoparticles from conductive materials. We had previously used this method to produce Au - Pd bimetallic nanoparticles with a mean diameter of around 6 nm. In this study we changed the operating parameters (e.g. spark energy and frequency, carrier gas type and flow rate) and analyzed the generated particles for their structures and compositions. X ray diffraction (XRD) patterns showed evidence of the formation of alloy phase in all the samples. Compositional analysis by Inductively Coupled Plasma (ICP) revealed that the average mixing ratio was influenced by the polarity, the spark frequency and the gap distance between anode and cathode.

scholarly journals Dielectric, impedance, modulus spectroscopy and AC conductivity studies on novel organic ferroelectric diisopropylammonium chloride (dipaCl)

2021 ◽  
pp. 2150015
Author(s):  
Mamataj Khatun ◽  
Ekramul Kabir
Keyword(s):  
Dielectric Property ◽  
Hydrochloric Acid ◽  
Dielectric Permittivity ◽  
Ac Conductivity ◽  
Conduction Mechanism ◽  
Arrhenius Equation ◽  
Methanol Solution ◽  
Power Exponent ◽  
Electrical Modulus ◽  
Modulus Spectroscopy

Organic molecular ferroelectric diisopropylammonium chloride (dipaCl) was successfully synthesized using diisopropylamine, hydrochloric acid (57%) and methanol solution. Dielectric permittivity, impedance, modulus spectroscopy and conductivity were systematically studied by Capacitance–Conductance ([Formula: see text] – [Formula: see text] measurements in the temperature range of 373–445 K. Dielectric property tests clearly show that the organic molecular ferroelectric dipaCl obeys Curies–Weiss law 1/[Formula: see text] = ([Formula: see text]–[Formula: see text]/[Formula: see text]. The real (Z′) and imaginary (Z′′) parts of the electrical modulus were calculated from the various values of 𝜀′ and 𝜀′′. It is shown that AC conductivity satisfies the relation [Formula: see text], where the power exponent [Formula: see text] depends on temperature and frequency. From Arrhenius equation, the activation energies [Formula: see text]and [Formula: see text] are also calculated which describes the complete conduction mechanism of dipaCl.

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