Dielectric, ac conductivity and modulus studies of sol–gel BaZrO2.9 compound

2020 ◽  
Vol 93 (8) ◽  
pp. 802-812
Author(s):  
Kh. Dhahri
Keyword(s):  
Ac Conductivity ◽  
Sol Gel ◽  
Modulus Studies

AC conductivity, dielectric and electrical modulus studies of bulk Zn0.95Co0.05O ceramic

2021 ◽  
Author(s):  
Pınar Oruç ◽  
Neslihan Turan ◽  
Yeşim Demirölmez ◽  
Ayten Seçkin ◽  
Şükrü Çavdar ◽  
...  
Keyword(s):  
Ac Conductivity ◽  
Electrical Modulus ◽  
Modulus Studies

Humidity Effects on Porous Silica Thin Films

1995 ◽  
Vol 411 ◽  
Author(s):  
J. R. Kokan ◽  
R. A. Gerhardt
Keyword(s):  
Thin Films ◽  
Ac Conductivity ◽  
Sol Gel ◽  
Porous Silica ◽  
Controlled Environment ◽  
Alkali Ions ◽  
Humidity Effects ◽  
Silica Thin Films ◽  
Environment Chamber ◽  
Humidity Sensitivity

ABSTRACTImpedance Spectroscopy is being used to study the humidity sensitivity of porous silica thin films. The films are processed via a colloidal sol-gel method which leaves some remnant potassium and sodium. Previous work on bulk porous silica samples processed by the same method showed that the dielectric properties and ac conductivity were very sensitive to changes in humidity. The aim of this work was to determine if the same dependencies could be found in the thin films. The capacitance, dielectric loss, and ac conductivity of the films were measured in a controlled environment chamber from 20–80% RH for frequencies ranging from 10Hz–10MHz. In addition to characterizing films with varying amounts of residual alkali ions obtained through leaching, we have also measured films that were surface doped with controlled amounts of KCl, LiCl, or NaCl. Relative humidity dependencies in the films are not as dramatic as in the bulk samples. The reasons for this behavior are not yet clear, but may be associated with the porosity, thickness, and surface area of the films.

Structural and electrical properties of lithium cobalt nanoferrites prepared by sol–gel method

2015 ◽  
Vol 29 (01) ◽  
pp. 1450255
Author(s):  
Victory Maisnam ◽  
Mamata Maisnam ◽  
Sumitra Phanjoubam
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Dielectric Loss ◽  
Ac Conductivity ◽  
Sol Gel ◽  
Interfacial Polarization ◽  
Frequency Variation ◽  
Gel Method ◽  
Sol Gel Method ◽  
Lithium Cobalt

Lithium cobalt nanoferrites having the compositional formula Li 0.5-x/2 Co x Fe 2.5-x/2 O 4 with x varying from 0.00 to 0.12 in steps of 0.03 were prepared by the chemical sol–gel method. Samples were heated at two different temperatures namely 300°C and 500°C for 4 h. Structural characterization of the samples was done using X-ray diffraction (XRD) technique and confirmed the formation of single phase with spinel structure in all the samples. From the XRD data, the lattice parameter was calculated and found to range from 82.87–83.35 nm while the crystallite size was found to be in the range 17–34 nm. Microstructural studies were carried out using the Scanning Electron Microscopy and revealed the microstructures with grain size ranging from 35–70 nm. Electrical properties like dielectric constant, dielectric loss and AC conductivity for these nanoferrites were investigated. The frequency variation of room temperature dielectric constant, dielectric loss and AC conductivity were studied in the frequency range 100 Hz–1 MHz, and a dispersive behavior was observed, which has been attributed to the Maxwell–Wagner type of interfacial polarization.

scholarly journals Dielectric and ac conductivity of ilmenite-type CdTiO3 ceramic

2019 ◽  
Vol 8 (3) ◽  
pp. 255
Author(s):  
Radouane Bahloul ◽  
Salaeddine Sayouri ◽  
TajEddine Lamcharfi
Keyword(s):  
Loss Tangent ◽  
Ac Conductivity ◽  
Conduction Mechanism ◽  
Sol Gel ◽  
Complex Impedance ◽  
Powder Sample ◽  
Hopping Conduction ◽  
Bulk Resistance ◽  
Tan Δ

<p class="Abstracttitle">Cadmium titanate CdTiO3 powder sample was prepared using the sol-gel route and calcined at 900°C. The dependence of the permittivity, loss tangent (tan δ) on the temperature in the range 40–600°C, and frequency in the range 103–2.106 Hz for the pure hexagonal ilmenite is reported. The ln(σac) versus T plots suggest that the conduction mechanism is of ionic hopping nature. The evolution of ln(σac) as a function of frequency suggests that the ionic hopping conduction decreases with the rise in temperature. The complex impedance plots revealed two depressed semicircular arcs indicating the bulk and interface contributions. The bulk resistance was found to increase with a decrease in temperature exhibiting typical semiconductor-like behavior.</p>

scholarly journals Structural, Dielectric, Magnetic and Magneto-Dielectric Properties of (1-x)BiFeO3–(x)CaTiO3 Composites

2021 ◽  
Author(s):  
Bushra Khan ◽  
Aditya Kumar ◽  
Preeti Yadav ◽  
Gulab Singh ◽  
Ashok Kumar ◽  
...  
Keyword(s):  
Ac Conductivity ◽  
Sol Gel ◽  
Negative Temperature ◽  
Tangent Loss ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Changes ◽  
Different Temperatures ◽  
Ferromagnetic Ordering ◽  
Jonscher’S Power Law

Abstract (1-x) BiFeO3–(x) CaTiO3 [(1-x) BFO – (x) CTO, (x = 0, 0.1, 0.2 and 0.3)] composites were synthesized using sol-gel chemical rout method. X-ray diffraction investigation shows the crystal structure changes from rhombohedral to monoclinic for 0 ≤ x ≤ 0.2, and it changes to orthorhombic at x ≤ 0.3. The Field Emission Scanning Electron Microscope (FESEM) investigation confirms the the microstructure consists of randomly oriented, homogenous, and non-uniform grains. The dielectric permittivity (ε) and tangent loss (tanδ) decreases with increasing frequency and show dielectric anomalies (as a hump) at different temperatures for different compositions. The incorporation of CTO, decreases three order of leakage current (up to x = 0.2) and significantly improve the magnetization and magneto-dielectric coupling. The frequency-dependent ac conductivity obeys Jonscher’s power law with large ac conductivity dispersion for higher frequencies with increasing CTO concentration. The variations of ac conductivity with the inverse of temperature obey the Arrhenius equation and show negative temperature coefficient of resistance (NTCR) behavior. The ferromagnetic (FM) properties in BFO-CTO increases significantly with an increase of the CTO concentration. The coercive field increases with increasing CTO concentration suggesting a competition between the antiferromagnetic and ferromagnetic ordering. At room temperature, all the samples show strong magneto-dielectric coupling.

Effect of Heat Treatment on Structural, Magnetic and Electric Properties of Z-Type Barium Cobalt Hexaferrite Powder

2014 ◽  
Vol 938 ◽  
pp. 24-29 ◽  
Author(s):  
Neha Solanki ◽  
G. Packiaraj ◽  
Rajshree B. Jotania
Keyword(s):  
Heat Treatment ◽  
Ac Conductivity ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Frequency Range ◽  
Treatment Conditions ◽  
Auto Combustion ◽  
Powder Samples ◽  
Combustion Technique

Z-type hexaferrite with composition Ba3Co2Fe24O41has been synthesized using a sol-gel auto combustion technique. The obtain combusted powder was sintered at 500 OC and followed by 950 OC for 4 hrs in a muffle furnace. The effect of different sintering temperature on crystal structure, crystallite size, microstructure and dielectric properties were systematically investigated. The prepared barium cobalt hexaferrite powder samples were characterized using different experimental techniques like FTIR, XRD, AC conductivity and specific magnetization measurements. It was observed from XRD results that heat treatment conditions play significant role in the formation of hexaferrite phase. AC conductivity measurements were carried out at room temperature in frequency range of 20Hz to 2MHz. All the samples show the frequency dependent phenomena, i.e. the AC conductivity increases with increasing frequency.

Relaxation process in PbI2–Ag2O–V2O5–B2O3 system: Dielectric, AC conductivity and modulus studies

2013 ◽  
Vol 178 (11) ◽  
pp. 775-784 ◽  
Author(s):  
Manish S. Jayswal ◽  
D.K. Kanchan ◽  
Poonam Sharma ◽  
Nirali Gondaliya
Keyword(s):  
Relaxation Process ◽  
Ac Conductivity ◽  
Modulus Studies

scholarly journals Dielectric and ac conductivity of ilmenite-type CdTiO3 ceramic

2019 ◽  
Vol 8 (3) ◽  
pp. 255-260
Author(s):  
Radouane Bahloul ◽  
Salaeddine Sayouri ◽  
TajEddine Lamcharfi
Keyword(s):  
Loss Tangent ◽  
Ac Conductivity ◽  
Conduction Mechanism ◽  
Sol Gel ◽  
Complex Impedance ◽  
Powder Sample ◽  
Hopping Conduction ◽  
Bulk Resistance ◽  
Tan Δ

Cadmium titanate CdTiO3 powder sample was prepared using the sol-gel route and calcined at 900°C. The dependence of the permittivity, loss tangent (tan δ) on the temperature in the range 40–600°C, and frequency in the range 103–2.106 Hz for the pure hexagonal ilmenite is reported. The ln(σac) versus T plots suggest that the conduction mechanism is of ionic hopping nature. The evolution of ln(σac) as a function of frequency suggests that the ionic hopping conduction decreases with the rise in temperature. The complex impedance plots revealed two depressed semicircular arcs indicating the bulk and interface contributions. The bulk resistance was found to increase with a decrease in temperature exhibiting typical semiconductor-like behavior

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