STRUCTURAL, ELECTRICAL AND MAGNETIC STUDIES OF Li–Zn–Ni FERRITES

2010 ◽  
Vol 24 (21) ◽  
pp. 2277-2282 ◽  
Author(s):  
IBETOMBI SOIBAM ◽  
SUMITRA PHANJOUBAM ◽  
CHANDRA PRAKASH ◽  
HARISH CHANDRA VERMA ◽  
R. K. KOTNALA
Keyword(s):  
Chemical Method ◽  
Room Temperature ◽  
Initial Permeability ◽  
Complex Permeability ◽  
Frequency Range ◽  
Magnetic Studies ◽  
Electrical And Magnetic Properties ◽  
Ni Substitution ◽  
Citrate Precursors ◽  
Mössbauer Analysis

Ni substituted Li – Zn ferrites with compositional formulas Li 0.4-0.5x Zn 0.2 Ni x Fe 2.4-0.5x O 4, where x = 0.02 ≤ x ≤ 0.1 in steps of 0.02, is synthesized by a chemical method using citrate precursors. The prepared ferrites are investigated for their structural, electrical and magnetic properties. Ni substitution significantly changes the characteristic properties of Li – Zn ferrites. There is an increase in grain growth as determined from SEM measurements. An increase in the room temperature DC resistivity is observed with the addition of Ni . The room temperature initial permeability shows an overall decrease with Ni concentration, which is explained with respect to saturation magnetization and supplemented by nuclear hyperfine field obtained from Mössbauer analysis. The variation of the complex permeability with frequency is measured over the frequency range of 100 Hz–1 MHz and dispersion is found. A possible mechanism contributing to the above process is discussed.

Investigation of Room Temperature Mössbauer Spectroscopy and Initial Permeability Properties of Al3+ Substituted Cobalt Ferrites

SPIN ◽  
2018 ◽  
Vol 08 (01) ◽  
pp. 1840005
Author(s):  
Rabia Pandit ◽  
Pawanpreet Kaur ◽  
K. K. Sharma ◽  
Mohd. Hashim ◽  
Ravi Kumar
Keyword(s):  
Loss Factor ◽  
Room Temperature ◽  
Magnetic Hyperfine Field ◽  
Initial Permeability ◽  
Wide Frequency Range ◽  
Ion Concentration ◽  
Frequency Range ◽  
High Frequencies ◽  
Relative Loss ◽  
Cobalt Ferrites

In the present work, Al[Formula: see text] substituted cobalt ferrites (CoFe[Formula: see text]AlxO4, [Formula: see text], 0.4, 0.6, 0.8) have been synthesized via standard solid-state reaction technique. The incorporation of Al[Formula: see text] ions in cobalt ferrite has been shown to play an important role in modifying the magnetic properties. The room temperature (300[Formula: see text]K) [Formula: see text]Fe Mössbauer spectra reveals that the studied samples show two characteristic ferromagnetic zeeman sextets at A and B-sites at lower Al[Formula: see text] ion concentration (i.e., up to [Formula: see text]). However, a paramagnetic relaxation has been noted for higher Al[Formula: see text] substitution (for [Formula: see text] and 0.8) samples. The dependence of the Mössbauer parameters such as isomer shift, quadrupole splitting, line width and magnetic hyperfine field on Al[Formula: see text] ion concentration has also been noted. The variations in initial permeability over a wide frequency range (125[Formula: see text]kHz to 30[Formula: see text]MHz) at 300[Formula: see text]K have been recorded. The fairly constant values of initial permeability and the low values of the relative loss factor of the order of 10[Formula: see text] to 10[Formula: see text] over the wide frequency range are the important findings of the present work. The observed low values of relative loss factor at high frequencies suggest that the studied ferrites are promising materials to be used in microwave applications.

scholarly journals Effect of Substitution of Al for Fe on the Magnetic Phase Transition and Initial Permeability of Zn-Co Ferrites

1970 ◽  
Vol 32 (2) ◽  
Author(s):  
AKM Zakaria ◽  
MA Hakim ◽  
MA Asgar
Keyword(s):  
Temperature Dependence ◽  
Room Temperature ◽  
Initial Permeability ◽  
Complex Permeability ◽  
Transition Temperatures ◽  
X Ray Diffraction ◽  
Al Content ◽  
Different Temperatures ◽  
Phase Spinel ◽  
Academy Of Sciences

The spinel oxides Zn0.4Co0.6AlxFe2-xO4 (x=0.0, 0.25, 0.50, 0.75 & 1.0) have been synthesized in the solid state sintering process in air. X-ray diffraction measurements have been carried out in order to check the phase which showed single phase spinel structure for all the samples. Initial permeability, frequency dependence of the complex permeability sintered at different temperatures has been measured on toroidal samples in the frequency range 1-500 KHz at room temperature. Temperature dependence of the complex permeability has been measured from room temperature to 435°C. Transition temperatures (TC) have been estimated from the temperature dependence of the permeability spectra for all the samples. It is found that the values of transition temperatures (TC) and initial permeability (mi) decrease with increasing substitution of Al content in the system. The values of TC obtained from permeability spectra are compared with those obtained from neutron diffraction data and magnetization measurements. doi: 10.3329/jbas.v32i2.2426 Journal of Bangladesh Academy of Sciences Vol.32(2) 2008 201-208

scholarly journals Photothermal, Photoelectric, and Photothermoelectric Effects in Bi-Sb Thin Films in the Terahertz Frequency Range at Room Temperature

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 76
Author(s):  
Mikhail K. Khodzitsky ◽  
Petr S. Demchenko ◽  
Dmitry V. Zykov ◽  
Anton D. Zaitsev ◽  
Elena S. Makarova ◽  
...  
Keyword(s):  
Thin Films ◽  
Terahertz Radiation ◽  
Room Temperature ◽  
Voltage Drop ◽  
Radiation Detection ◽  
Radiation Detectors ◽  
Thz Radiation ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range

The terahertz frequency range is promising for solving various practically important problems. However, for the terahertz technology development, there is still a problem with the lack of affordable and effective terahertz devices. One of the main tasks is to search for new materials with high sensitivity to terahertz radiation at room temperature. Bi1−xSbx thin films with various Sb concentrations seem to be suitable for such conditions. In this paper, the terahertz radiation influence onto the properties of thermoelectric Bi1−xSbx 200 nm films was investigated for the first time. The films were obtained by means of thermal evaporation in vacuum. They were affected by terahertz radiation at the frequency of 0.14 terahertz (THz) in the presence of thermal gradient, electric field or without these influences. The temporal dependencies of photoconductivity, temperature difference and voltage drop were measured. The obtained data demonstrate the possibility for practical use of Bi1−xSbx thin films for THz radiation detection. The results of our work promote the usage of these thermoelectric materials, as well as THz radiation detectors based on them, in various areas of modern THz photonics.

scholarly journals Dielectric Spectroscopy Analysis of Liquid Crystals Recovered from End-of-Life Liquid Crystal Displays

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2873
Author(s):  
Ana Barrera ◽  
Corinne Binet ◽  
Frédéric Dubois ◽  
Pierre-Alexandre Hébert ◽  
Philippe Supiot ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
End Of Life ◽  
Room Temperature ◽  
Liquid Crystal Displays ◽  
Dielectric Anisotropy ◽  
Frequency Range ◽  
Spectroscopy Analysis ◽  
Diamond Nanoparticles ◽  
Nematic Phases ◽  
Universal Law

In the present work, the dielectric properties of recycled liquid crystals (LCs) (non-purified, purified, and doped with diamond nanoparticles at 0.05, 0.1, and 0.2 wt%) were investigated. The studied LC mixtures were obtained from industrial recycling of end-of-life LC displays presenting mainly nematic phases. Dielectric measurements were carried out at room temperature on a frequency range from 0.1 to 106 Hz using an impedance analyzer. The amplitude of the oscillating voltage was fixed at 1 V using cells with homogeneous and homeotropic alignments. Results show that the dielectric anisotropy of all purified samples presents positive values and decreases after the addition of diamond nanoparticles to the LC mixtures. DC conductivity values were obtained by applying the universal law of dielectric response proposed by Jonscher. In addition, conductivity of the doped LC mixtures is lower than that of the undoped and non-purified LC.

High Frequency Dielectric Response of the Ionic Liquid N-Methyl-N-ethylpyrrolidinium Dicyanamide

2007 ◽  
Vol 60 (1) ◽  
pp. 6 ◽  
Author(s):  
Simon Schrödle ◽  
Gary Annat ◽  
Douglas R. MacFarlane ◽  
Maria Forsyth ◽  
Richard Buchner ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Dielectric Loss ◽  
Dielectric Relaxation ◽  
High Frequency ◽  
Dielectric Response ◽  
Room Temperature ◽  
Room Temperature Ionic Liquid ◽  
Dielectric Relaxation Spectroscopy ◽  
Frequency Range ◽  
Fast Rotation

A study of the room-temperature ionic liquid N-methyl-N-ethylpyrrolidinium dicyanamide by dielectric relaxation spectroscopy over the frequency range 0.2 GHz ≤ ν ≤ 89 GHz has revealed that, in addition to the already known lower frequency processes, there is a broad featureless dielectric loss at higher frequencies. The latter is probably due to the translational (oscillatory) motions of the dipolar ions of the IL relative to each other, with additional contributions from their fast rotation.

Electromagnetic Property of La0.7Sr0.3MnO3/Ag Composite at High Frequency

2015 ◽  
Vol 655 ◽  
pp. 182-185
Author(s):  
Ke Lan Yan ◽  
Run Hua Fan ◽  
Min Chen ◽  
Kai Sun ◽  
Xu Ai Wang ◽  
...  
Keyword(s):  
High Frequency ◽  
Single Phase ◽  
Low Frequency ◽  
Electromagnetic Property ◽  
High Frequency Range ◽  
Frequency Range ◽  
Free Electron Concentration ◽  
Theoretical Simulation ◽  
Electrical And Magnetic Properties ◽  
Three Phase

The phase structure, and electrical and magnetic properties of La0.7Sr0.3MnO3(LSMO)-xAg (xis the mole ratio,x=0, 0.3, 0.5) composite were investigated. It is found that the sample withx=0 is single phase; the samples withx=0.3 and 0.5 present three phase composite structure of the manganese oxide and Ag. With the increasing of Ag content, the grain size of the samples increases and the grain boundaries transition from fully faceted to partially faceted. The permittivity of spectrum (10 MHz - 1 GHz) and the theoretical simulation reveal that the plasma frequencyfpincrease with Ag content, due to the increasing of free electron concentration, which is further supported by the enhancement of conductivity. While for the permeability (μr'), theμr'decrease with the increasing of Ag content at low frequency range (f< 20 MHz), while at the relative high frequency range (f> 300 MHz), theμr'increased with Ag content. Therefore, the introduction of elemental Ag resulted in a higherμr'at the relative high frequency range.

scholarly journals Studies on the Preservation of Raw Cow’s Milk by Chemical Method

1970 ◽  
Vol 42 (3) ◽  
pp. 317-326 ◽  
Author(s):  
F Rokhsana ◽  
UK Das ◽  
R Yeasmin ◽  
A Nahar ◽  
S Parveen
Keyword(s):  
Hydrogen Peroxide ◽  
Chemical Method ◽  
Room Temperature ◽  
Storage Period ◽  
Total Coliform ◽  
Human Consumption ◽  
Milk Products ◽  
E Coli ◽  
Keeping Quality ◽  
Control Milk

Studies carried out to develop a technique for the preservation of cow's milk in raw condition using hydrogen peroxide (H2O2) as a preservative. Fresh cow’s milk was collected and experiments were conducted by four treatments in order to achieve the optimum condition of storage. The treatments were with various concentration of H2O2 starting from 0.05 %, 0.1 %, 0.2 %, 0.3 %, 0.4 %, & 0.5 %. Treated milk with 0.05 % concentration of H2O2 had storage period of 20 days compared to that of the control one (5 days only) in refrigerated temperature (±8°C). On the other hand hydrogen peroxide treated milk (0.05 %) had a storage period of 8 hours at room temperature (±28°C). Results also showed that the higher concentration of H2O2 had no effect on storage period than that of control. Milk products like kheer and halawa prepared by treated milk and stored for 20 days showed almost nil growth of total coliform and E. coli which means that food products prepared from hydrogen peroxide treated milk is safe for human consumption. Key words: Raw, Storage, Hydrogen peroxide, Preservative, keeping quality, Pasteurization, deteriorated, MPN. Bangladesh J. Sci. Ind. Res. 42(3), 317-326, 2007

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