عبده كمال دياب حماية

استاذ - قسم الفيزياء

كلية العلوم

العنوان: جامعة سوهاج - كلية العلوم بسوهاج - قسم الفيزياء


he annealing influence onto the electrical and magnetic  behavior of magnetoresistive/insulator system
his investigation is mainly concerned with the effect of annealing temperature (600, 700, 800 and 900 °C) in air for (La0.7Ba0.3MnO3)1–x /(NiO)x with x = 0 and x = 0.10 samples. It was shown that the annealing temperature does not affect the structure and parameters of rhombohedral lattice of the samples. However, it is observed that the annealing treatment has ... إقراء المزيد

Synthesis, characterization and low field magnetotransport of Nd0.6Sr0.4MnO3/CrO3composite
Abstract:(Nd0.6Sr0.4MnO3)1-x/(CrO3)xwith x=0.0–0.030 step 0.005 weight% composites have been prepared by the solid state reaction process. The X-ray and scanning electron microscopic manifest that all composites are a single orthorhombic phase and there are no CrO3 grains separated from NdSrMnO matrix. The electrical measurements have revealed an increase of resistivity and a decrease of metal semiconductor transition with increasing CrO3. The ... إقراء المزيد

2016 | الكلمات المفتاحية Thin film, sputtering, , Optical , energy gap, refractive index,
Thin films of aluminum zinc oxide are prepared using DC magnetron sputtering. It was found that changing the thickness of the film as well as the pressure of argon affect the transmittance, optical gap, width of the band tails of the localized state, refractive index, real and imaginary parts of the dielectric function. The real and imaginary parts of optical ... إقراء المزيد

2016 | الكلمات المفتاحية Magnetic materials, crystal structure, electrical properties, Phase transitions,
Influence of heat treatment on the magnetic and magnetocaloric properties in Nd0.6Sr0.4MnO3 compound
In the present investigation, the effect of annealing temperature on the structural, electrical transport and the magnetocaloric effect of Nd0.6Sr0.4MnO3manganites have been studied. Rietveld refinement of XRD data reveals that all samples are single phase with a space group (Pnma). Heat treatment enhances the grain size and decreases the porosity. All samples suffer Curie transition from ferromagnetic to paramagnetic. Magnetocaloric ... إقراء المزيد

Enhanced electro-magnetic properties in La0.7Sr0.3MnO3/ZrO2 composites
(La0.7 Sr0.3MnO3)1-x/(ZrO2)x (x=0.0–0.150, step 0.025) composites have been prepared via solid state reaction process. The X-ray diffraction and scanning electron microscopic observations indicate that there are ZrO2grains separated from La0.7Sr0.3MnO3matrix. It has been found that the inclusion of ZrO2content decreases the conductivity, magnetization and metal–semiconductor transition, whereas it increases the low field magnetoresistance. Possible effects of grain boundaries on the ... إقراء المزيد

2015 | الكلمات المفتاحية In35Sb45Se20−xTex, Thin films, XRD, Electrical properties, Annealing temperature,
Structural  and  electrical  properties  of  In35Sb45Se20−xTexchalcogenide thin  films
The structural and electrical properties of the as-prepared and annealed In45Sb35Se20−xTex thin films with different compositions (x = 2.5, 5, 7.5, 10, 12.5 and 15 at.%) prepared by electron beam evaporation method are studied. The XRD patterns of the as-prepared thin film show that the investigated compositions have amorphous and polycrystalline structure depending on the Te content. After annealing the ... إقراء المزيد

2014 | الكلمات المفتاحية CdO NWs, Vapor transport, FT-IR, SEM, Ellipsometer, SEM-EDX, Photoluminescence,
Synthesis, photoluminescence and optical constants evaluations of ultralong CdO nanowires prepared by vapor transport method
Ultralong CdO nanowires (NWs) were synthesized on Au coated Si and quartz substrates by using vapor transport method. The synthesis temperature was chosen via thermal gravimetry analysis (TGA) and it was 1150C. The formation of CdO was confirmed by energy dispersive analysis of X-ray (EDAX) and Fourier transform infrared (FT-IR) spectroscopy analysis. The CdO nanowires was found to grow via ... إقراء المزيد

2013 | الكلمات المفتاحية Alloys; Chalcogenides; Electri,
Effect of composition on transport properties of Ge10AsxTe902x chalcogenide system
Chalcogenide bulk alloys of Ge10AsxTe90-x(x=20, 25, 30, 35, 40, 45 and 55) system were prepared by the conventional melt quench-technique. The dc electrical conductivityrand thermoelectric power (TEP) measurements were carried out in the temperature ranges from 83 to 353 K and from 253 to 353 K, respectively. The variations of bothrand TEP with temperature proved n-type semiconducting behavior of these ... إقراء المزيد

2011 | الكلمات المفتاحية The resistivity·Colossal magne, Curie temperature,
Effect of Li-Substitution on the Resistivity and Magnetoresistance of LaMnOy
The temperature dependence of the resistivity (ρ) and magneto-resistance (MR) effect of La1−xLixMnOy (x=0.05, 0.1, 0.15, 0.2 & 0.25 at.%) fixed valence doped compounds were studied between 80 and 320 K. X-ray powder diffraction (XRD) at room temperature shows that the samples are single phase. The resistivity of all samples with and without magnetic field shows a metal–semiconductor (M–S) transition ... إقراء المزيد

Structural and optical properties of In35Sb45Se20xTex phase-change thin films
Physical properties of In35Sb45Se20xTexthin films with different compositions (x¼2.5, 5, 7.5, 10, 12.5 and 15 at%) prepared by electron beam evaporation method are studied. X-ray diffraction results indicate that the as-evaporated films depend on the Te content and the crystallized compounds consist mainly of Sb2Se3with small amount of Sb2SeTe2. Transmittance and reflectance of the films are found to be thickness ... إقراء المزيد