scholarly journals Composition, Temperature and Frequency Dependent Magnetic, Dielectric and Electrical Properties of Magnesium-Zinc Ferrites

2012 ◽  
Vol 36 (2) ◽  
pp. 199-212 ◽  
Author(s):  
M Mahbubur Rahman ◽  
Md Shahin Sheak ◽  
Soheli Pervin ◽  
Nasir Uddin ◽  
Farid Ahmed ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Curie Temperature ◽  
Interfacial Polarization ◽  
Initial Permeability ◽  
Dielectric Behavior ◽  
Dielectric Dispersion ◽  
Cu Content ◽  
Virgin State ◽  
Academy Of Sciences ◽  
Magnetic Dielectric

Polycrystalline spinel MgxZn0.3Cu0.7-2xFe2+xO4, where x = 0.10, 0.20, 0.25, 0.30 and 0.35  ferrites (hereafter abbreviated as Mg-Zn) have been prepared by conventional double sintering technique. The samples were sintered at 1250°C in air for 6 hours. Measurements have been done at temperature and frequency ranges of 0 - 350°C and 0 - 500 kHz, respectively. In this work, some extrinsic magnetic properties such as Curie temperature, initial permeability, loss factor, quality factor, dielectric constant and resistivity of the samples have been studied. The Curie temperature and loss tangent of the samples decreased with increase in Cu-content whereas permeability, Qfactor, resistivity and dielectric constant have been noticed to be increased with the increase in Cucontent.  The decrease in Curie temperature related to fact of weakening the strength of exchange AB  interaction. Maxwell-Wagner type of interfacial polarization might have found correlated with  the normal dielectric behavior of the samples, however no relaxation peaks were observed in the  dielectric dispersion curves of the Mg-Zn samples in virgin state or doped state. DOI: http://dx.doi.org/10.3329/jbas.v36i2.12963 Journal of Bangladesh Academy of Sciences, Vol. 36, No. 2, 199-212, 2012

scholarly journals Effect of Ca-substitution on the Magnetic and Dielectric Properties of Mn-Zn Ferrites

2012 ◽  
Vol 4 (2) ◽  
pp. 297 ◽  
Author(s):  
M. M. Rahman ◽  
P. K. Halder ◽  
F. Ahmed ◽  
T. Hossain ◽  
M. Rahaman
Keyword(s):  
Dielectric Constant ◽  
Curie Temperature ◽  
Loss Tangent ◽  
Sintering Temperature ◽  
Initial Permeability ◽  
Q Factor ◽  
Dielectric Polarization ◽  
Ca Substitution ◽  
Magnetic And Dielectric Properties ◽  
Curie Temperature Tc

Spinel Mn-Zn ferrites with composition MnxZn0.4Ca0.6-2xFe2+xO4, where x = 0.10, 0.15, 0.20, 0.25 and 0.30 have been prepared by conventional ceramic technique sintered at    1300 °C for 4 hours. The influence of Ca-substitution on various properties of Mn-Zn ferrites have been studied in this work. Investigations were carried out by the measurements of Curie temperature, permeability, loss tangent, Q-factor, dielectric constant and AC resistivity of the samples. Curie temperature (Tc), the real part of initial permeability (µ´), loss tangent (tan ?), and AC resistivity have been found to be decreased while the Q-factor increases with the increase in Ca-content. The frequency characteristics of the dielectric constant and AC resistivity have been found to be decreased as the frequency increases. Maxwell-Wagner interfacial type of dielectric polarization was observed with the addition of Ca-content over the entire range of frequency considered. Keywords: Spinel ferrites; Sintering temperature; Initial permeability; Dielectric constant.© 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v4i2.9752 J. Sci. Res. 4 (2), 297-306 (2012)

scholarly journals Effects of Li2O additive on structural, magnetic and electrical properties of Ni-Mg ferrite

2014 ◽  
Vol 38 (1) ◽  
pp. 7-18 ◽  
Author(s):  
Sheikh Mohi Uddin Rumy ◽  
Mahabub Alam Bhuiyan ◽  
MH Mesbah Ahmed ◽  
Kazi Hanium Maria ◽  
MA Hakim ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Spinel Ferrite ◽  
Lattice Parameter ◽  
Initial Permeability ◽  
Dielectric Behavior ◽  
Ferromagnetic Behavior ◽  
Xrd Pattern ◽  
Dielectric Constant Measurement ◽  
Academy Of Sciences ◽  
Magnetic And Electrical Properties

The effects of Li2O additives on the structural, magnetic and electrical properties of Ni0.5Mg0.5Fe2O4, prepared by conventional double sintering ceramic technique were investigated. The X-raydiffraction (XRD) pattern of the prepared samples showed single phase cubic spinel structure.Variation of lattice parameter has been observed with the variation of Li2O content. Theenhancement of bulk density has been observed for 2 mol% Li2O additive, but further increase inLi2O concentration, these values decrease. Enhancement of initial permeability (??) have beenobserved for the sample with 2 mol% Li2O additives while it decreases for higher concentration ofLi2O. The Curie temperature is found to decrease with the increase in Li2O additive. The resistivityincreases with increasing additive content and showed a significant dispersion with frequency,which is the normal ferromagnetic behavior. The dielectric constant (??) measurement showed thenormal dielectric behavior of spinel ferrite. Possible explanation for the observed features arediscussed. DOI: http://dx.doi.org/10.3329/jbas.v38i1.20198 Journal of Bangladesh Academy of Sciences, Vol. 38, No. 1, 7-18, 2014

scholarly journals Complex Permeability and Transport Properties of Zn Substituted Cu Ferrites

1970 ◽  
Vol 34 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Kazi Hanium Maria ◽  
Shamima Choudhury ◽  
MA Hakim
Keyword(s):  
Dielectric Constant ◽  
Transport Properties ◽  
Initial Permeability ◽  
Complex Permeability ◽  
Normal Behaviour ◽  
Zn Addition ◽  
Zn Concentration ◽  
Zn Content ◽  
Sem Micrograph ◽  
Academy Of Sciences

Zn doped Cu ferrite of the composition Cu1-xZnxFe2O4 ferrites for x = 0, 0.1, 0.2, 0.3, 0.4, 0.5,0.6 prepared by standard double sintering ceramic technique. SEM micrograph of all the samplesrevealed that the grain sizes decrease gradually with the increase of Zn content and has greatinfluence on the magnetic and transport properties. Permeability is found to increase with increasein Zn content up to x = 0.4 and then slightly decreases with further increase in Zn. The values ofrelative quality factor (RFQ) changes with Zn concentration. Room temperature DC resistivitychanges significantly with Zn addition. The variation of the resistivity versus frequency was studiedand the dielectric constant of the system has a variation quite opposite to that of the AC resistivity.Dielectric constant shows the normal behaviour of the ferrite materials that can be explained by theinterfacial polarization as predicted by Maxwell and Wagner.Key words: Microstructure; Initial permeability; Dielectric constant; DC resistivityDOI: 10.3329/jbas.v34i1.5486Journal of Bangladesh Academy of Sciences, Vol.34, No.1, 1-8, 2010

scholarly journals Variation of Transport Properties and Apparent Density of Soft Nickel Ferrite

2012 ◽  
Vol 36 (1) ◽  
pp. 137-142
Author(s):  
Mahabub Alam Bhuiyan ◽  
Shamima Choudhury ◽  
Sheikh Manjura Hoque
Keyword(s):  
Dielectric Constant ◽  
Apparent Density ◽  
Sintering Temperature ◽  
Resistivity Measurement ◽  
Great Influence ◽  
Dielectric Behavior ◽  
Prepared Sample ◽  
Electrical And Dielectric Properties ◽  
Polarization Theory ◽  
Academy Of Sciences

Polycrystalline NiFe2O4 was prepared from Analytical Grade powder of NiO and Fe2O3 by conventional double sintering technique. The apparent density of the prepared sample increases with the increase in sintering temperature and consequently the porosity decreases which has a great influence on electrical and dielectric properties of soft ferrites. It is observed that with the increase in temperature, the DC resistivity of the prepared sample decreases which confirms the semiconducting behavior of the prepared NiFe2O4. In addition to this, at room temperature it is observed that the resistivity decreases with the increase in sintering temperature. Variations of activation energy have been observed for different sintering temperature and are in agreement with the resistivity measurement. Frequency dependence of dielectric constant (?) has been measured and shows the normal dielectric behavior of the prepared sample which can be explained on the basis of Koop’s two layer model and Maxwell-Wagner polarization theory. Along with these, enhancement of dielectric constant has been observed with the increase in sintering temperature. DOI: http://dx.doi.org/10.3329/jbas.v36i1.10929 Journal of Bangladesh Academy of Sciences, Vol. 36, No. 1, 137-142, 2012

scholarly journals Dielectric and transport properties of Zn-substituted cobalt ferrites

2013 ◽  
Vol 37 (1) ◽  
pp. 73-82 ◽  
Author(s):  
Amrita Khan ◽  
Mahabub Alam Bhuiyan ◽  
Golam Dastegir Al Quaderi ◽  
Kazi Hanium Maria ◽  
Shamima Choudhury ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Transport Properties ◽  
Bulk Density ◽  
Dielectric Behavior ◽  
X Ray Diffraction ◽  
Cobalt Ferrites ◽  
Zn Concentration ◽  
Zn Content ◽  
Increasing Temperature ◽  
Academy Of Sciences

Effect of Zn content on the dielectric and transport properties of CoZnxFe2-xO4 (x = 0.0, 0.1, 0.2, 0.3 and 0.4), prepared by standard double sintering ceramic technique, sintered at 1000°C for 4 hours were investigated. The X-ray diffraction (XRD) pattern of the prepared samples showed single phase inverse-spinel structure without any detectable impurity. Lattice constant of the samples increased with the increasing Zn concentration which follows Vegard’s law. The theoretical densities of these samples remained almost constant whereas the bulk density decreased with Zn content up to x = 0.2. But with further increase of Zn content the bulk density increased. The porosity of the prepared samples showed the opposite trend. The dielectric constant (??) measurement showed the normal dielectric behavior of the prepared ferrite. The DC electrical resistivity of the prepared samples decrease with increasing temperature which indicates the semiconducting behavior of the prepared ferrites. The Zn concentration showed pronounced effect on the resistivity at room temperature. Possible explanation for the observed features of densities, porosity, dielectric constant and resistivity of the studied samples are discussed. DOI: http://dx.doi.org/10.3329/jbas.v37i1.15683 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 1, 73-82, 2013

scholarly journals Investigation of the correlation between microstructure and hysteresis curve of li0.5-x/2cuxfe2.5-x/2o4 ferrites

2014 ◽  
Vol 37 (2) ◽  
pp. 121-129
Author(s):  
M Samir Ullah ◽  
S Manjura Hoque ◽  
FA Khan
Keyword(s):  
Grain Size ◽  
Electron Microscope ◽  
Room Temperature ◽  
Initial Permeability ◽  
Hysteresis Curve ◽  
Cu Content ◽  
Lithium Ferrites ◽  
Average Grain Size ◽  
Academy Of Sciences ◽  
Scanning Electron

Cu substituted lithium ferrites with composition Li0.5-x/2CuxFe2.5-x/2O4 (where x = 0.0, 0.1, 0.2, 0.4 and 0.6) were synthesized by conventional double sintering ceramic technique and sintered at 1100oC for 3 hours in the normal atmosphere. The microstructures for the samples of different compositions were examined by scanning electron microscope (SEM). The average grain size was determined by the linear intercept method which demonstrates that the average grain size increases with the increase of Cu content. The initial permeability was found to increase with Cu content, x, which is attributed to increase of grain size of the samples. The parameters of hysteresis curve have been determined at room temperature by B-H Loop Tracer. It was found that coercivity and initial permeability were closely related to each other which are mainly governed by the anisotropy and grain size of the mixed ferrites. DOI: http://dx.doi.org/10.3329/jbas.v37i2.17551 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 2, 121-129, 2013

Preparation and electrical properties of Ni–Cu–Zn system doped with the magnesium oxide

2014 ◽  
Vol 28 (23) ◽  
pp. 1450157 ◽  
Author(s):  
O. M. Hemeda ◽  
A. Tawfik ◽  
D. M. Hemeda ◽  
A. M. Elsheekh
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Curie Temperature ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Lattice Parameter ◽  
Initial Permeability ◽  
Spectra Analysis ◽  
Cationic Distribution ◽  
Tan Δ

A sery of ferrite samples, Ni 0.1 Cu 0.2 Mg x Zn 0.7-x Fe 2 O 4, (x = 0.00, 0.15, 0.25, 0.35, 0.45, 0.55 and 0.70) have been prepared by the standard ceramic techniques, sintered at 1200°C for 2 h, and their crystalline structures were investigated by using X-ray diffraction, which confirmed the formation of Ni 0.1 Cu 0.2 Mg x Zn 0.7-x Fe 2 O 4 phase. The presence of Mg content increases the crystallinity of the given ferrite which is considered as catalyst for the accomplishment of the solid state reaction. The lattice parameter and crystallite size were calculated from XRD. The cationic distribution was estimated from the theoretical values of lattice parameters. The IR spectra analysis has been studied. The dielectric constant for the ferrite system Ni – Cu – Zn gradually increases with temperature up to nearly Curie temperature and then increase sharply beyond the Tc. The Curie temperature obtained from the [Formula: see text] versus T is in agreement with the Curie temperature obtained from other measurements. Dielectric loss tangent ( tan δ) has the same behavior as dielectric constant [Formula: see text]. A minimum value of dielectric loss tangent ( tan δ) for the system " Ni – Cu – Zn " was observed at x = 0.45. Magnetic permeability has been studied. The dependence of initial permeability on temperature exhibit a peak which is called Hopkinson peak (HP) in the vicinity of Curie temperature and confirmed the phase purity of ferrite sample. The increasing of porosity and decreasing of grain size play an important role in decreasing μi. It is clear that the value of Tc is found to increase by increasing the concentration of diamagnetic substitution Mg for " Ni – Cu – Zn " system.

scholarly journals Dielectric Properties, Resistivity and Curie temperature Of Co doped CdNi perminvar ferrite

1970 ◽  
Vol 32 (1) ◽  
pp. 23-32 ◽  
Author(s):  
DK Saha ◽  
MA Hakim
Keyword(s):  
Dielectric Constant ◽  
Curie Temperature ◽  
Single Phase ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Two Samples ◽  
Good Consistency ◽  
Increasing Temperature ◽  
Academy Of Sciences

CdNi perminvar ferrites doped with Co were prepared through the solid-state reaction using conventional ceramic technique. The compositions of the ferrite were Co0.02Cd0.20Ni0.58Fe2.2O4 and Co0.02Cd0.28Cd0.28Ni0.50Fe2.2O4. X-ray diffraction study of the samples indicates the single phase of perminvar ferrites. Lattice parameter of the samples was found to be 8.3676 and 8.4249 Å for sample no. (a) of Co0.02Cd0.20Ni0.58Fe2.2O4 and sample no. (b) of Co0.02Cd0.28Ni0.50Fe2.2O4, respectively. The porosity of the samples was found to be 10.03 and 9.53%. The values of Curie temperature for the two samples were found to be 472 ± 1 and 405 ± 1°C, respectively. Resistivity of the samples was measured from room temperature up to 600°C. At 30°C resistivity was found to be 334 and 456 ohm-cm, respectively. Frequency dependent dielectric constant for the two samples has been determined from the experimental capacitance values. The value of dielectric constant at frequency, f = 1 kHz and sintering temperature Ts = 1250°C was found to be 16.6 × 106 and 56.1 × 106, for sample no. (a) and (b), respectively. Dielectric constant was observed 3.5 times higher in the Cd rich sample of Co0.02Cd0.28Ni0.50Fe2.2O4 and Co0.02Cd0.20Ni0.58Fe2.2O4. Temperature dependent dielectric constant has been measured for the samples in the temperature range of 30 - 250°C. The value of dielectric constant initially increases slowly with increasing temperature and then rises sharply until reaching a certain temperature, then it begins to decrease with further increase of temperature. Anomalies in the resistivity curves have good consistency with the temperature dependent dielectric constant and Curie temperature values. doi: 10.3329/jbas.v32i1.2438 Journal of Bangladesh Academy of Sciences, Vol. 32, No. 1, 23-32, 2008

Influence of Ca-Doping on Structural, Magnetic and Dielectric Properties of Ba3Co2-xCaxFe24O41 Hexaferrite Powders

2015 ◽  
Vol 241 ◽  
pp. 226-236 ◽  
Author(s):  
Neha Solanki ◽  
Rajshree B. Jotania
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Sol Gel ◽  
Calcium Content ◽  
Combustion Method ◽  
Dielectric Behavior ◽  
Dielectric Parameters ◽  
Ca Doping ◽  
Auto Combustion ◽  
Magnetic And Dielectric Properties

Influence of Ca substitution on structural, magnetic and dielectric properties of Ba3Co2-xCaxFe24O41(where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0), prepared by Sol-Gel auto-combustion method, has been investigated in present studies. The obtained powder was sintered at 950 oC for 4 hrs. in the static air atmosphere. Structural analysis of Ca-doped Ba3Co2-xCaxFe24O41powders revealed pure Z-type hexaferrite phase at low temperature. The frequency dependent dielectric constant (Єʹ) and magnetic properties such as remanent magnetization (Mr), saturation magnetization (Ms) and coercivity (Hc) were studied. It is observed that coercivity increased gradually with increase in calcium content. The real dielectric constant (Єʹ) and dielectric loss tangent (tan δ) were studied in the frequency range of 20Hz to 2MHz. The dielectric parameters for all samples show normal dielectric behavior as observed in hexaferrites. Contents of Paper

COMPARATIVE STUDY OF DIELECTRIC BEHAVIOR OF Mn0.4Zn0.6Fe2O4 NANOFERRITE BY CITRATE PRECURSOR METHOD

2008 ◽  
Vol 22 (16) ◽  
pp. 2537-2544 ◽  
Author(s):  
PREETI MATHUR ◽  
ATUL THAKUR ◽  
M. SINGH
Keyword(s):  
Particle Size ◽  
Dielectric Constant ◽  
Comparative Study ◽  
Average Particle Size ◽  
Dielectric Behavior ◽  
Average Particle ◽  
Oxidizing Agent ◽  
Precursor Method ◽  
Citrate Precursor ◽  
Citrate Precursor Method

In the present work, comparative study of the dielectric behavior of Mn 0.4 Zn 0.6 Fe 2 O 4 ferrite synthesized with and without H 2 O 2 (hydrogen peroxide) has been presented. The dc resistivity has been improved by the citrate precursor method as compared to the ceramic method, and it is further improved by the addition of H 2 O 2, which acts as a strong oxidizing agent. We have shown by means of X-ray diffraction that the resulting ferrite is made up of nanocrystallites and the average size of these nanocrystallites–calculated by Scherrer's formula–depends on the polarizer. The average particle size was found to be ~70 nm with H 2 O 2 and ~88 nm without H 2 O 2. The particle size is further confirmed by scanning electron microscopy. Both the results are found to be in good agreement. The decrease in dielectric constant and dielectric loss factor by addition of oxidizing agent is justified by inverse proportionality between the resistivity and dielectric constant. Possible mechanisms contributing to these processes have been discussed.

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