Dielectric Behaviour of Nanocrystalline Ni-Zn Ferrites Prepared by Oxalate Co-Precipitation Method

2013 ◽  
Vol 645 ◽  
pp. 56-59
Author(s):  
Shinde J. Tukaram ◽  
Gadkari B. Ashok ◽  
Vasambekar N. Pramod
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Ac Conductivity ◽  
Interfacial Polarization ◽  
Dielectric Behaviour ◽  
Precipitation Method ◽  
High Resistivity ◽  
Ceramic Method ◽  
Low Dielectric ◽  
Co Precipitation

Nickel–zinc ferrites with chemical formula Ni1-xZnxFe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0) were prepared by oxalate co-precipitation method. The dielectric constant (ε') dielectric loss (tanδ) and AC conductivity (σac) of all the samples were determined at room temperature in the frequency range 20Hz -1MHz. The dielectric constant and dielectric loss are much smaller than those for samples prepared by ceramic method. The dielectric behaviour is attributed to the Maxwell–Wagner type interfacial polarization. AC conductivity of all the samples lies in the range 1.20×10-8 to 54.7×10-8 Ω-1cm-1. Low dielectric loss and high resistivity suggest the suitability of these ferrites for high frequency applications.

Dielectric study of Al3+ substituted Fe3O4 ferrite nanoparticles

2014 ◽  
Vol 28 (28) ◽  
pp. 1450193 ◽  
Author(s):  
N. Kumari ◽  
Vinod Kumar ◽  
S. K. Singh
Keyword(s):  
Dielectric Loss ◽  
Dielectric Permittivity ◽  
Ac Conductivity ◽  
Interfacial Polarization ◽  
Precipitation Method ◽  
Dielectric Study ◽  
Hopping Mechanism ◽  
Tan Δ ◽  
Co Precipitation ◽  
Increasing Temperature

Al 3+ substituted nanoparticles i.e., FeAl x Fe 2-x O 4(x = 0.2, 0.4, 0.6) have been synthesized by the chemical co precipitation method. Crystalline phase of synthesized particles was confirmed by XRD pattern. Particle size of as obtained samples was found in the range of 24–34 nm. Dielectric loss (tan δ, dielectric permittivity (ε′) and ac conductivity (σ ac ) were evaluated as a function of frequency, composition and temperature using impedance analyzer in the frequency range of (1000 Hz–5 MHz) and temperature range of (300–473 K). AC conductivity (σ ac ) was found to decrease with increase in Al 3+ doping which has been explained on the basis of hopping mechanism. The variation of dielectric loss ( tan δ, dielectric permittivity (ε′), ac conductivity (σ ac ) with temperature and frequency can be explained on the basis of Maxwell–Wagner type of interfacial polarization and hopping mechanism between ferrous and ferric ions at the octahedral site. DC electrical resistivity was found to decrease with increasing temperature indicating that the substituted ferrites have semiconductor like behavior. Activation energy was found to increase with increasing Al 3+ ion content.

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 Synthesis and Study of Structural and Dielectric Properties of Dy-Ho Doped Mn-Zn Ferrite Nanoparticles

2021 ◽  
Author(s):  
Krishtappa Manjunatha ◽  
Veerabhadrappa Jagadeesha Angadi ◽  
Brian Jeevan Fernandes ◽  
Keralapura Parthasarathy Ramesh
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Ac Conductivity ◽  
Ferrite Nanoparticles ◽  
The Real ◽  
Low Dielectric ◽  
Zn Ferrite ◽  
Xrd Patterns ◽  
The One

The Dy-Ho doped Mn-Zn Ferrite nanoparticles have been synthesized by solution combustion method using mixture of fuels as glucose and urea. The synthesized samples of structural properties were characterized through XRD (X-ray diffraction) and dielectric properties were studied through impedance analyzer. The XRD patterns of all samples confirms the spinel cubic structure having space group Fd3m. Further all synthesized samples reveal the single-phase formation without any secondary phase. The lattice parameters and hopping lengths were increases with increase of Dy-Ho concentration. SEM micrographs shows the porous nature for all samples. The crystallite size increases with increase of Dy-Ho concentration. The Dielectric properties of all the samples were explained by using Koop’s phenomenological theory. The real part of dielectric constant, imaginary part of dielectric constant and dielectric loss tangent were decreases with increase of frequency. Th AC conductivity increases with increase of frequency. The real part of impedance spectra decreases with increase of frequency for all samples. The Cole-Cole plots shows the one semicircle for all samples. The high ac conductivity and low dielectric loss observed for all samples at high frequency region and this samples are reasonable for power transformer applications at high frequencies.

scholarly journals The Effect of Co doping on Structural, Optical and Dielectric Behaviour of TiO2 Nanoparticles

2021 ◽  
Vol 71 (03) ◽  
pp. 390-394
Author(s):  
Harpreet Singh Mahal ◽  
Bhanu Partap Singh ◽  
Ravi Kant
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Tio2 Nanoparticles ◽  
Ac Conductivity ◽  
Anatase Phase ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Cobalt Ions ◽  
Co Doping ◽  
Vis Spectroscopy

Chemical precipitation method was used to synthesise pure and Co-doped TiO2 nanoparticles. The synthesised nanoparticles were studied for its structural optical and dielectric properties. X-Ray diffraction (XRD) confirmed the anatase phase with the tetragonal structure obtained for both samples. No extra peak was obtained in the pattern indicates that cobalt ions were successfully incorporated. The crystallite size of both samples were determined by using Debye-Scherrer’s method, and it was found that it decreases with the dopant addition. UV vis spectroscopy was performed to study the optical properties of both samples. The dielectric constant (εʹ), dielectric loss and ac conductivity (σac) of both samples were studied against the frequency. The dielectric constant, dielectric loss and ac conductivity results showed that Co-doping has a significant effect.

scholarly journals Structural, electric and dielectric properties of Eu-doped SrBi2Nb2O9 ceramics obtained by co-precipitation route

2018 ◽  
Vol 12 (1) ◽  
pp. 72-77 ◽  
Author(s):  
Mohamed Afqir ◽  
Amina Tachafine ◽  
Didier Fasquelle ◽  
Mohamed Elaatmani ◽  
Jean-Claude Carru ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Ac Conductivity ◽  
Ftir Spectra ◽  
Significant Shift ◽  
Dielectric Losses ◽  
Frequency Range ◽  
Co Precipitation

This paper presents a study of the structure and dielectric properties of Eu-doped SrBi2Nb2O9 ceramics prepared by co-precipitation route and sintered at 850?C. The materials were examined using XRD and FTIR methods. XRD data indicated the formation of well crystallized structure of the pure and doped SrBi2Nb2O9, without the presence of undesirable phases. FTIR spectra do not bring a significant shift in the band positions. Moreover, the AC conductivity, dielectric constant and dielectric loss of the ceramics were determined through the frequency range [50 kHz-1MHz]. In particular, the dielectric constant (??) and dielectric losses (tan ?) of the SrBi2Nb2O9 and SrBi1.6Eu0.4Nb2O9 ceramics were measured as a function of temperature at various frequencies.

Skin–core structured fluorinated MWCNTs: a nanofiller towards a broadband dielectric material with a high dielectric constant and low dielectric loss

2018 ◽  
Vol 6 (9) ◽  
pp. 2370-2378 ◽  
Author(s):  
Yang Liu ◽  
Cheng Zhang ◽  
Benyuan Huang ◽  
Xu Wang ◽  
Yulong Li ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
High Dielectric Constant ◽  
Dielectric Material ◽  
Epoxy Composite ◽  
Low Dielectric ◽  
High Dielectric

A novel skin–core structured fluorinated MWCNT nanofiller was prepared to fabricate epoxy composite with broadband high dielectric constant and low dielectric loss.

scholarly journals Crown ether-containing polyimides with high dielectric constant

RSC Advances ◽  
2017 ◽  
Vol 7 (38) ◽  
pp. 23309-23312 ◽  
Author(s):  
Ting Yang ◽  
Wenhui Xu ◽  
Xinwen Peng ◽  
Haoqing Hou
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Crown Ether ◽  
High Dielectric Constant ◽  
Low Dielectric ◽  
High Dielectric

Crown ether-containing polyimides possess high dielectric constant and low dielectric loss, without sacrificing other properties.

Photosensitive Polyimide having low loss tangent for RF application

2018 ◽  
Vol 2018 (1) ◽  
pp. 000476-000482 ◽  
Author(s):  
Masao Tomikawa ◽  
Hitoshi Araki ◽  
Yohei Kiuchi ◽  
Akira Shimada
Keyword(s):  
Molecular Structure ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
High Frequency ◽  
Low Dielectric Constant ◽  
Low Loss ◽  
Elongation At Break ◽  
Low Dielectric ◽  
The Poor

Abstract Progress of 5G telecommunication and mm radar for autopilot, high frequency operation is required. Insulator materials having low loss at high frequency is desired for the applications. We designed the low dielectric constant, and low dielectric loss materials examined molecular structure of the polyimide and found that permittivity 2.6 at 20GHz, dielectric loss 0.002. Furthermore, in consideration of mechanical properties such as the toughness and adhesion to copper from a point of practical use. Dielectric properties largely turned worse when giving photosensitivity. To overcome the poor dielectric properties, we designed the photosensitive system. After all, we successfully obtained 3.5 of dielectric constant and 0.004 of dielectric loss, and 100% of elongation at break. In addition, we offered a B stage sheet as well as varnish. These materials are applicable to re-distribution layer of FO-WLP, Interposer and other RF applications for microelectronics.

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