scholarly journals IR Spectra, Elastic and Dielectric Properties of Li–Mn Ferrite

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
S. A. Mazen ◽  
N. I. Abu-Elsaad
Keyword(s):  
Dielectric Properties ◽  
Ir Spectra ◽  
Lattice Parameter ◽  
Exponential Factor ◽  
Ceramic Method ◽  
Ion Substitution ◽  
Rigidity Modulus ◽  
Binding Forces ◽  
Hopping Model ◽  
Model Frequency

Polycrystalline ferrites, , (where and ), were prepared by using ceramic method. Single phase cubic structure was confirmed by X-ray diffractometer. The lattice parameter “a” was found to increase with increasing ion substitution. IR spectra of the samples were recorded from 200 to 1000 cm−1. The two primary bands corresponding to tetrahedral and octahedral were observed at about 575 cm−1 and 370 cm−1, respectively. Elastic properties of these mixed ferrites were estimated as a function of composition. Young's modulus , rigidity modulus , bulk modulus , Debye temperature (), and mean sound velocity () were calculated from the transverse () and longitudinal () wave velocities. The variation of elastic moduli with composition was interpreted in terms of binding forces between the atoms of spinel lattice. AC conductivity and dielectric properties of the samples were measured at room temperature over 100 Hz–1 MHz. The electrical conduction mechanism could be explained with the electron hopping model. Frequency exponential factor was calculated and it was found between 0.4 and 0.8.

scholarly journals Structural and Elastic Properties of Li-Ni Ferrite

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
S. A. Mazen ◽  
T. A. Elmosalami
Keyword(s):  
Cation Distribution ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Ceramic Method ◽  
X Ray ◽  
Lattice Constants ◽  
Wave Velocities ◽  
Rigidity Modulus ◽  
Binding Forces ◽  
Good Agreement

Li-Nickel ferrites with the chemical formula () have been prepared by the ceramic method. The spinel structure in homogenous state was realized by X-ray diffraction analysis. The lattice parameter has been determined for each composition and found to be nearly constant over the whole range of Ni concentration (= 0.83 nm ± 0.01). The cation distribution for each composition has been suggested. The experimental and theoretical lattice constants were found to be in good agreement with each other confirming the agreeability of the suggested cation distribution. The analysis of IR spectra indicates the presence of splitting in the absorption band due to the presence of small amounts of Fe2+ ions in the ferrite system. The force constants for tetrahedral and octahedral sites have been determined. Young’s modulus (E), rigidity modulus (G), bulk modulus (B), Debye temperature (), and transverse () and longitudinal () wave velocities have been determined. The variation of elastic moduli with composition has been interpreted in terms of binding forces between the atoms of spinal lattice.

Influence of Excess Bi2O3 and Na2Co3 on Crystal Structure and Microstructure of Bismuth Sodium Titanate Ceramics

2011 ◽  
Vol 474-476 ◽  
pp. 1711-1714 ◽  
Author(s):  
Panadda Sittiketkron ◽  
Arrak Klinbumrung ◽  
Theerachai Bongkarn
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Perovskite Phase ◽  
Average Particle Size ◽  
Sodium Titanate ◽  
Solid State Reaction Method ◽  
Lattice Parameter ◽  
Rhombohedral Structure ◽  
Average Particle ◽  
Average Grain Size

This study investigated the influence of excess Bi2O3 and Na2CO3 on the crystal structure, microstructure and dielectric properties of (Bi0.5Na0.5)TiO3 (BNT) ceramics. The BNT ceramics were synthesized using the solid-state reaction method with various excess Bi2O3 and Na2CO3 levels (0, 1, 2, 3 and 4 mol%). The X-ray characterization revealed that all samples had a rhombohedral structure. A pure perovskite phase was obtained in all samples. The lattice parameter a tended to increase with increased excess Bi2O3 and Na2CO3 content in the calcined powders and sintered ceramics. The average particle size increased while, the average grain size tended to decreased with increased of excess Bi2O3 and Na2CO3 content. The depolarization temperature (Td) and the Curie temperature (Tc) were slightly decreased with the increase of excess Bi2O3 and Na2CO3 content. The dielectric properties were related to the density.

scholarly journals Composition Dependence of Elastic Moduli of Mixed Cobalt-Zinc Ferrites Prepared by Citrate Precursor Method

2019 ◽  
Vol 32 (1) ◽  
pp. 31-35
Author(s):  
Ch. Vinuthna ◽  
Sandupatla Raju ◽  
D. Ravinder
Keyword(s):  
Synthesis Method ◽  
Ultrasonic Pulse ◽  
Elastic Module ◽  
Pulse Transmission ◽  
Precursor Synthesis ◽  
Rigidity Modulus ◽  
Binding Forces ◽  
Ultrasonic Pulse Transmission ◽  
Elastic Modules ◽  
Citrate Precursor

CoxZn1-xFe2O4 nanoparticles were prepared by chemical citrate precursor synthesis method. The Young’s modulus ‘E’ and the rigidity modulus ‘n’ of mixed cobalt-zinc ferrites have been determined by the ultrasonic pulse transmission technique at 1 MHz. The elastic modules of the ferrites were corrected to zero porosity using the formulae of Harselman and Fulrath. The observed variation of the elastic module with composition has been interpreted on the basis of binding forces between the atoms of the spinal lattice. A linear relationship between Debye temperature ØD and average sound velocity Vm has also been observed.

THE EFFECT OF AMOUNT TANTALUM DOPING ON THE PROPERTIES OF MgCuZn FERRITES

2011 ◽  
Vol 25 (19) ◽  
pp. 2583-2591 ◽  
Author(s):  
A. TAWFIK ◽  
M. Z. SAID ◽  
O. M. HEMEDA
Keyword(s):  
Electrical Resistivity ◽  
Sintered Density ◽  
Sintering Temperature ◽  
Lattice Parameter ◽  
Initial Permeability ◽  
Maximum Density ◽  
Preparation Process ◽  
Iron Ions ◽  
Ceramic Method ◽  
Jump Length

The systems MgCuZn Fe 2 O 4 doped (0–0.6 wt% Ta) are prepared by the general ceramic method using the sintering temperature at 1200°C. The variations of the sintered density, lattice parameter, jump length of electrons, and initial permeability were studied. A maximum density was obtained at 1200°C during the preparation process. The electrical resistivity decreases with increasing tantalum ( Ta ) content upto 0.1 wt% and then increases for higher concentrations. The initial permeability and the change carries mobility increase upto 0.1 Ta and then decreases. The jump length decreases with enhancing Ta ions because the substitution of Ta ion with small size instead of Fe 3+ at the A sites increase the concentration of iron ions at the B sites. The increase of the iron content causes the decrease of the jump length of electrons between Fe 3+ and Fe 2+. These improvements of the magnetic properties give some light about the importance of these compositions to be used in technology.

Effect of Sn2+Ion Substitution on Dielectric Properties of (Ba,Ca)TiO3Ferroelectric Ceramics

2010 ◽  
Vol 49 (9) ◽  
pp. 09MC04 ◽  
Author(s):  
Shoichiro Suzuki ◽  
Toshikazu Takeda ◽  
Akira Ando ◽  
Takashi Oyama ◽  
Nobuyuki Wada ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Ion Substitution

scholarly journals Effects Of Cd On Physical And Some Magnetic Properties Of Co-Cd Ferrites

1970 ◽  
Vol 35 (2) ◽  
pp. 229-235 ◽  
Author(s):  
Saroaut Noor ◽  
SS Sikder ◽  
M Samir Ullah ◽  
MA Hakim ◽  
Shireen Akhter
Keyword(s):  
Curie Temperature ◽  
Lattice Parameter ◽  
Initial Permeability ◽  
X Ray Diffraction ◽  
Ceramic Method ◽  
X Ray ◽  
Cobalt Ferrites ◽  
Vegard’S Law ◽  
Ray Density ◽  
Curie Temperature Tc

Polycrystalline samples of Cd substituted cobalt ferrites with composition Co1-xCdxFe2O4 (x = 0.0- 0.6 in steps of 0.1) were prepared by double sintering ceramic method. The samples were sintered at 1050°C for 3 hours. X-ray diffraction pattern of the samples showed single phase cubic spinel structure. It was found that the lattice parameter increases linearly with increasing Cd content following Vegard’s law. The apparent density and X-ray density exhibited similar behavior. The Curie temperature Tc has been determined from the temperature dependence of permeability. It was found that the Curie temperature continuously decreased with increasing Cd content and is attributed to the weakening of JAB exchange interaction. The initial permeability, μ' increases with increasing Cd content up to x = 0.6 and then decreases. Key words: Co-Cd ferrite; Lattice parameter; Permeability DOI: http://dx.doi.org/10.3329/jbas.v35i2.9429 JBAS 2011; 35(2): 229-235

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