Electrical, Dielectrical and Magnetic Properties of Zr-Mn Doped Nano-Ferrites

2012 ◽  
Vol 510-511 ◽  
pp. 301-306
Author(s):  
K. Khan ◽  
Ashari Maqsood
Keyword(s):  
Activation Energy ◽  
Electrical Resistivity ◽  
Drift Mobility ◽  
Nominal Composition ◽  
Frequency Range ◽  
Energy Increase ◽  
Dielectric Parameters ◽  
Dc Electrical Resistivity ◽  
Low Field ◽  
Mn Doped

We measured the dc electrical resistivity as a function of temperature and dielectric parameters in the frequency range 100 Hz to 3 MHz of nanosized Zr-Mn spinel ferrites with nominal composition CoFe2-2xZrxMnxO4(0.1x0.4). The dc electrical resistivity decreased with the rise in temperature for all the samples, showing a semiconductor like behavior. From the dc electrical resistivity the activation energy and drift mobility are determined. Both the drift mobility and activation energy increase with a rise inx. The dielectric constant, dielectric (losses) and ac electrical resistivity as a function of frequency are also reported. The low field ac magnetic susceptibility measurement showed that the ferrimagentic transition temperature is in the range of 4395 K to 6585 K.

Preparation, Structural and Electrical Properties of Nanocrystalline Zr-Mn Cobalt-Ferrite Synthesized by the Co-Precipitation Method

2012 ◽  
Vol 510-511 ◽  
pp. 248-254
Author(s):  
K. Khan
Keyword(s):  
Activation Energy ◽  
Electrical Resistivity ◽  
Frequency Band ◽  
Electrical Characterization ◽  
Drift Mobility ◽  
Precipitation Method ◽  
Dc Electrical Resistivity ◽  
Ft Ir ◽  
Ir Study ◽  
Co Precipitation

The present study describes the preparation, structural and electrical characterization of nanosized Zr-Mn cobalt-ferrites. The nominal compositions CoFe2-2xZrxMnxO4 (0.10.4) have been synthesized by the co-precipitation method. These nanopowder products were sintered in furnace at temperature of 800 °C for 8 hour with a heating rate of 10οC/min to obtain these ferrites. The nanopowder was evaluated using XRD, FT-IR and SEM. The XRD data showed that all the samples are of single phase and the crystallite size is found in the range of 2630 nm. The lattice constant (a), X-ray density (dx), porosity (P) and bulk density (dm) are also calculated from XRD data. FT-IR study confirms the presence of ferrite functional groups. The IR spectra of Zr-Mn ferrite system have been analyzed in the frequency range 400650 cm-1. It revealed two prominent bands υ1 and υ2 which are assigned to tetrahedral and octahedral metal complexes, respectively. The position of the highest frequency band is around 550 cm-1 while the lower frequency band is around 425 cm-1. The structural properties are also analyzed on scanning electron microscopy (SEM) at room temperature. Additionally, the dc electrical resistivity decreased with the rise in temperature for all the samples, showing a semiconductor like behavior. From the dc electrical resistivity the activation energy and drift mobility are determined. Both the drift mobility and activation energy increase with a rise in x.

Physical, Electrical and Magnetic Properties of Nanocrystalline Zr-Mn-Co Prepared by Co-Precipitation Route

2011 ◽  
Vol 14 ◽  
pp. 113-121
Author(s):  
Ashari Maqsood ◽  
Kishwar Khan ◽  
M. Anis-ur-Rehman ◽  
Muhammad Ali Malik
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Electrical Resistivity ◽  
Drift Mobility ◽  
Spinel Ferrites ◽  
Average Particle ◽  
Dc Electrical Resistivity ◽  
X Ray ◽  
General Chemical ◽  
Co Precipitation

Spinel ferrites, which have the general chemical composition MeFe2O4, (Me = Co, Zn, Ni) are of interest due to their electronic, magnetic and optical properties. Nanosized Co-Zr-Mn spinel ferrites with nominal composition CoFe2-2xZrxMnxO4 (0.1≤ x≤0.4) have been prepared by the co-precipitation route. The products are characterized by X-ray diffraction, scanning electron microscopy (SEM) at room temperature, dc electrical resistivity as a function of temperature and dielectric parameters in the frequency range of 100 Hz to 3 MHz are also measured. The lattice constants agree with usual spinel ferrites. The particle size calculated from X-ray data by the Scherrer formula is in the range of 28-30 nm, while the average particle size varies from 15-25 nm obtained from the SEM measurements, X-ray density (Dx), Porosity (P) and bulk density (Dm) for all the samples are calculated. The dc electrical resistivity decreased with the rise in temperature for all the samples, showing a semiconductor like behavior. From the dc electrical resistivity the activation energy and drift mobility are determined. Both the drift mobility and activation energy increase with a rise in x. The dielectric constant, dielectric loss and ac electrical resistivity as a function of frequency are also reported. The low field ac magnetic susceptibility measurement showed that the ferrimagentic transition temperature is in the range of 439±5 K to 658±5 K.

Structural, electrical and microwave properties of (Sr0.6Ca0.4) (CoyMn1−y) O3 (0.2 ≤ y ≤ 1.0) thick film ceramics

2016 ◽  
Vol 33 (1) ◽  
pp. 9-14 ◽  
Author(s):  
R.P. Pawar ◽  
Vijaya Puri
Keyword(s):  
Electrical Resistivity ◽  
Thick Film ◽  
Microwave Absorption ◽  
Thick Films ◽  
Alumina Substrate ◽  
Microwave Properties ◽  
Frequency Range ◽  
Content Type ◽  
Dc Electrical Resistivity ◽  
Permittivity And Permeability

Purpose – This paper aims to study the structural, electrical and microwave properties of (Sr0.6Ca0.4) (CoyMn1−y) O3 (0.2 ≤ y ≤ 1.0) thick-film ceramics. Design/methodology/approach – The thick films of (Sr0.6Ca0.4) (CoyMn1−y) O3 (0.2 ≤ y ≤ 1.0) on the alumina substrate have been delineated using screen printing technique. The structural analysis was carried out using an X-ray diffraction method and scanning electron microscopy. The direct current (DC) electrical resistivity is measured using a two-probe method. Microwave absorption was studied in the 8-18 GHz frequency range by using the Waveguide Reflectometer Method. The permittivity and permeability in the 8-18 GHz frequency range were measured by using Voltage Standing Wave Ratio slotted section method. Findings – The thick films have orthorhombic perovskite structure with dominant (020) plane. By using first-principle calculation method, theoretical and experimental lattice parameter and cell volume of (Sr0.6Ca0.4) (CoyMn1−y) O3 are matched with each other. The cobalt content changes the morphology from plates to needles. The DC electrical resistivity increases with increase in Co content and decreases with increase in temperature. (Sr0.6Ca0.4) (CoyMn1−y) O3 thick film shows 75 per cent microwave absorption both in the X band and Ku band. The microwave permittivity and permeability decreases with increase in frequency and Co content. Originality/value – Structural, electrical and microwave properties of (Sr0.6Ca0.4) (CoyMn1−y) O3 (0.2 ≤ y ≤ 1.0). Thick film ceramics on alumina substrate is reported for the first time.

Magnetic, structural and dc electrical resistivity studies on the divalent cobalt substituted Ni–Zn ferrite system

2015 ◽  
Vol 29 (12) ◽  
pp. 1550067 ◽  
Author(s):  
M. Siva Ram Prasad ◽  
B. B. V. S. V. Prasad ◽  
B. Rajesh Babu
Keyword(s):  
Activation Energy ◽  
Grain Size ◽  
Electrical Resistivity ◽  
Lattice Constant ◽  
Room Temperature ◽  
Error Function ◽  
Positive Contribution ◽  
Dc Electrical Resistivity ◽  
Cobalt Substitution ◽  
Zn Ferrite

Polycrystalline cobalt substituted Ni – Zn ferrite with composition Ni 0.65-x Co x Zn 0.35 Fe 2 O 4(x = 0.00–0.25 insteps of 0.05) have been prepared through the conventional solid state ceramic method. Calcination and sintering have been performed in air atmosphere at 950°C and 1250°C for 4 h and 2 h, respectively followed by natural cooling to room temperature. X-ray diffraction patterns of all samples indicated the formation of the single spinel structure and the accurate lattice parameter for each composition has been determined using the Nelson–Riley error function. The increase in lattice constant on cobalt substitution is attributed to the ionic radius difference between the displaced and the substituted ion. The variation in lattice constant on incorporation of Co 2+ ion indicates its solubility into the spinel lattice and noticeable modification in structural properties have been observed. The observed increase in the saturation magnetization and Curie temperature with the increase in the Co 2+ substitution is due to its higher magnetic moment compared to that of Ni 2+, improvement in the A–B exchange interaction mechanism and large positive contribution to magnetic anisotropy due to presence of Co 2+ when they are at the octahedral sites. The observed variation in the initial magnetic permeability and the magnetic loss factor with cobalt substitution measured at a low frequency of 1 KHz have been attributed to the modification in the density, porosity, grain size and anisotropy contributions. A nearly comparable variation is observed in the room temperature dc electrical resistivity and activation energy for conduction and is attributed to the modification in structure, role and nature of cobalt ions and the microstructure aspects like grain size and pore concentration. The activation energy values in the range of 0.28 to 0.36 eV suggest a possible electron hopping. The observed changes in the structural and the magnetic and electrical properties have all been discussed in the light of exiting understanding.

Synthesis and characterization of magnetically separable La1−x Bi x Cr1−y Fe y O3 and photocatalytic activity evaluation under visible light

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Aamir Ghafoor ◽  
Ismat Bibi ◽  
Sadia Ata ◽  
Farzana Majid ◽  
Shagufta Kamal ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Visible Light ◽  
Orthorhombic Phase ◽  
Xrd Analysis ◽  
Dielectric Parameters ◽  
Dc Electrical Resistivity ◽  
Storage Devices ◽  
Energy Devices ◽  
Prepared Material ◽  
Magnetically Separable

Abstract A series of Bi and Fe doped La1−x Bi x Cr1−y Fe y O3 (x = 0.00–0.10 and y = 0.02–0.12) perovskites were fabricated through a facile microemulsion method and were characterized by XRD, DC electrical-resistivity, dielectric, VSM, and UV–Visible measurements. Orthorhombic phase of synthesized substituted chromite nanocrystallite was confirmed by powdered XRD analysis with crystallite size in 47.8–32.9 nm range. DC electrical resistivity was observed to increase from 1.70–39.99 × 108 Ω-cm. Dielectric parameters analyzed in frequency range of 20 kHz–20 MHz were decreased, while magnetic parameters were observed to increase with the increase in dopant (Bi+3 and Fe+3) concentration. Whereas coercivity values was low (narrow hysteresis loop), which indicate the soft ferromagnetic of the prepared material materials which are quite useful to employ in storage devices and electronics. Moreover, La1−x Bi x Cr1−y Fe y O3 degraded 90.80% Rhodamine B dye under visible light irradiation within 55 min. The increase in electrical resistivity, while decrease in dielectric parameters was also observed with increase in dopant concentration, ferromagnetic nature and excellent photocatalytic properties make this material suitable for high frequency energy devices, microwave appliances as well as an excellent magnetically separable photocatalyst for the purification of contaminated wastewater.

scholarly journals Electrical Conductivity and Dielectric Properties of Bulk Glass V2O5 (ZnO, PbO) SrO FeO

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
M. S. Aziz ◽  
A. G. Mostafa ◽  
A. M. Youssef ◽  
S. M. S. Youssif
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Dielectric Dispersion ◽  
Bulk Glass ◽  
Frequency Range ◽  
Glassy System ◽  
Dielectric Parameters

The AC conductivity and dielectric parameters of the glassy system of (70-x) V2O5· x(Zn/Pb)· 10SrO · 20FeO (x = 0, 5, 10, and 15) glasses have been investigated. The frequency and temperature dependence of dielectric constant (ε′) and dielectric loss (ε′′) is studied in the frequency range 100 Hz–5 MHz and in the temperature range 300–460 K. Dielectric dispersion is observed in all samples as Zn/Pb increase content in the (70-x)V2O5· x(Zn/Pb)·10SrO·20FeO systems. These results are explained on the basis of a Debye-type relaxation. It is also observed that the activation energy increases on increasing the Zn/Pb contents in this system.

DC electrical resistivity studies and structure of Ni0.5Zn0.5CrxFe2-xO4 nanoferrites

2015 ◽  
Vol 29 (16) ◽  
pp. 1550101 ◽  
Author(s):  
M. Siva Ram Prasad ◽  
B. Rajesh Babu ◽  
K. V. Ramesh ◽  
K. Trinath
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Electrical Resistivity ◽  
Differential Thermal Analysis ◽  
Spinel Phase ◽  
Structural Defects ◽  
Scanning Electron Micrographs ◽  
Dc Electrical Resistivity ◽  
Dta Studies ◽  
Scanning Electron

Chromium substituted Ni – Zn nano ferrite samples with composition Ni 0.5 Zn 0.5 Cr x⋅ Fe 2-x O 4 (x = 0.00 to 0.25 in steps of 0.05) have been prepared by autocombustion method employing citric acid as an oxidant. Structural, morphological and microstructural characterizations were done on the sintered powders at 1000°C while the DC electrical resistivity studies have been performed on the pellets sintered at the same temperature. The thermogravimetric and differential thermal analysis (TG-DTA) studies indicated the presence of broad exotherm and valley centered about temperature of 400°C. The formation of single-spinel phase has been observed for all the samples. The ionic packing coefficient, vacancy parameter and fulfillment coefficient have all been obtained for each composition. The scanning electron micrographs showed the formation of fine grains with size very less than 1 μm in all samples with a little agglomeration. The observed variation in DC electrical resistivity and activation energy with Cr 3+ substitution are attributed to the modifications in microstructure, structural defects and the influence of Cr 3+ ions with support of hopping mechanism.

Effect of Cu substitution on magnetic and DC electrical resistivity properties of Ni–Zn nanoferrites

2021 ◽  
Author(s):  
K. Chandramouli ◽  
P. Anantha Rao ◽  
B. Suryanarayana ◽  
Vemuri Raghavendra ◽  
Shaik Jesus Mercy ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Dc Electrical Resistivity ◽  
Cu Substitution

scholarly journals Studying of dielectric spectra of YCu0.15Mn0.85O3 solid solution with the use of complex conductivity

2021 ◽  
pp. 2160013
Author(s):  
A. V. Nazarenko ◽  
A. V. Pavlenko ◽  
Y. I. Yurasov
Keyword(s):  
Solid Solution ◽  
Electrical Conductivity ◽  
Model Description ◽  
Complex Conductivity ◽  
Electrophysical Properties ◽  
Approximation Model ◽  
Frequency Range ◽  
Dielectric Parameters ◽  
Frequency Behavior ◽  
Complex Electrical Conductivity

This work presents the results of studying the electrophysical properties of the YCu[Formula: see text]Mn[Formula: see text]O3 solid solution in the range of temperatures of [Formula: see text] = 26–400[Formula: see text]C and frequency range of [Formula: see text] = 102–105 Hz. A model description of the revealed dispersion of dielectric parameters in the material is made. The nonclassical modified Havriliak–Negami model written for complex electrical conductivity was used as an approximation model. It is shown that the application of this model almost exactly describes the frequency behavior of the dielectric constant [Formula: see text]/[Formula: see text], the dielectric loss tangent tg[Formula: see text] as well as the real and imaginary parts of complex conductivity [Formula: see text] and [Formula: see text]. The results of this work are an important step in identifying the opportunities and understanding the applications of this model.

scholarly journals RODICA GALASIU; IOAN GALASIU; NICULAE POPA; VASILICA CHIVU

1998 ◽  
Vol 6 (6) ◽  
pp. 63-69
Author(s):  
RODICA GALASIU ◽  
IOAN GALASIU ◽  
NICULAE POPA ◽  
VASILICA CHIVU
Keyword(s):  
Activation Energy ◽  
Electrical Resistivity

Five recipes of SnO2 - based ceramics masses were prepared. The influence of CeO2 additions on the properties of ceramic masses were studied. It was found that the CeO2 additions increase the electrical resistivity of these ceramic masses, but the electrical resistivity decreases with the CeO2 content. The CeO2 additions have the same influence on the activation energy for conductivity.

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