Structural Characterization of the Chromium-Iron Alloy Formed by Thermal Diffusion Processes

2013 ◽  
Vol 651 ◽  
pp. 284-288 ◽  
Author(s):  
Roberto Baca Arroyo
Keyword(s):  
Thermal Diffusion ◽  
Diffusion Processes ◽  
Iron Alloy ◽  
Magnetic Coupling ◽  
Magnetic Ordering ◽  
X Ray Diffraction ◽  
Lattice Constants ◽  
Air Atmosphere ◽  
Direct Band

We have investigated the chromium-iron alloy and compared it to the oxides α-Fe2O3 (Eg = 4.8eV) and α-Cr2O3 (Eg = 2.1eV). It is known that α-Cr2O3 and α-Fe2O3 both adopt a corundum-type structure, but display differences in the lattice constants, direct band gap, and magnetic ordering of the cations. The chromium-iron alloy was synthesized by thermal diffusion processes of both chromium and iron thin-films in air atmosphere conditions. We have studied the elastic distortions related to nature of the relative strains as well as magnetic coupling between Fe and Cr from the X-ray diffraction studies.

scholarly journals Characterization of dislocations in germanium layers grown on (011)- and (111)-oriented silicon by coplanar and noncoplanar X-ray diffraction

2015 ◽  
Vol 48 (3) ◽  
pp. 655-665 ◽  
Author(s):  
Andrei Benediktovitch ◽  
Alexei Zhylik ◽  
Tatjana Ulyanenkova ◽  
Maksym Myronov ◽  
Alex Ulyanenkov
Keyword(s):  
Dislocation Line ◽  
Complementary Metal Oxide Semiconductor ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Misfit Dislocations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Silicon And Germanium

Strained germanium grown on silicon with nonstandard surface orientations like (011) or (111) is a promising material for various semiconductor applications, for example complementary metal-oxide semiconductor transistors. However, because of the large mismatch between the lattice constants of silicon and germanium, the growth of such systems is challenged by nucleation and propagation of threading and misfit dislocations that degrade the electrical properties. To analyze the dislocation microstructure of Ge films on Si(011) and Si(111), a set of reciprocal space maps and profiles measured in noncoplanar geometry was collected. To process the data, the approach proposed by Kaganer, Köhler, Schmidbauer, Opitz & Jenichen [Phys. Rev. B, (1997),55, 1793–1810] has been generalized to an arbitrary surface orientation, arbitrary dislocation line direction and noncoplanar measurement scheme.

SYNTHESIS AND CHARACTERIZATION OF ZnO NANORODS AND NANOWIRES USING PVP AS CAPPING

2009 ◽  
Vol 08 (03) ◽  
pp. 285-287 ◽  
Author(s):  
M. ESKANDARI ◽  
V. AHMADI ◽  
Sh. AHMADI
Keyword(s):  
Solution Method ◽  
Zno Nanorods ◽  
Green Emission ◽  
Zno Nanowires ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Solution Method ◽  
Air Atmosphere ◽  
20 Nm

In this study, ZnO nanowires are synthesized via ZnO nanorods at low temperature by using zinc acetate dehydrate and polyvinylpyrrolidone as precursor and capping, respectively. We use chemical solution method for synthesis of ZnO nanowires. Samples are characterized by means of scanning electron microscopy and X-ray diffraction. First, the nanorods are prepared at 300°C temperature, and then they are put into the furnace under air atmosphere at 450°C for 2 h. It is observed that nanowires with 20 nm diameter are produced. Photoluminescence spectra of nanorods and nanowires are compared. It shows that intensity of ultraviolet peak in the nanowires decreases but in contrast the intensity of green emission part increases. This is because, the surface effects such as oxygen vacancies increase in the structures of ZnO .

scholarly journals Preparation and characterization of cobalt and copper oxide nanocrystals

2019 ◽  
Vol 37 (3) ◽  
pp. 347-352
Author(s):  
A. H. Moharram
Keyword(s):  
Microwave Irradiation ◽  
Copper Oxide ◽  
Chemical Precipitation ◽  
High Dispersion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Direct Band ◽  
Cuo Nanocrystals

AbstractCopper oxide and cobalt oxide (Co3O4, CuO) nanocrystals (NCs) have been successfully prepared using microwave irradiation. The obtained powders of the nanocrystals (NCs) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric (TGA) analysis and Fourier-transform infrared spectroscopy. The obtained results confirm the presence of both nanooxides which have been produced during chemical precipitation using microwave irradiation. TEM micrographs have shown that the obtained nanocrystals are characterized by high dispersion and narrow size distribution. The results of X-ray diffraction confirmed those obtained from the transmission electron microscope. Optical absorption analysis indicated the direct band gap for both kinds of the nanocrystals.

scholarly journals Effect of Process Parameter Optimization in Reducing Sintering Temperature in the Synthesis and Characterization of Ba(Zn1/3Nb2/3)O3

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
P. K. Bajpai ◽  
K. N. Singh
Keyword(s):  
Perovskite Phase ◽  
Impedance Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Microwave Dielectric ◽  
Pure Perovskite Phase ◽  
Higher Temperature ◽  
Ac Conduction

Controlling the cooling rate during calcination and sintering, phase pure perovskite Ba(Zn1/3Nb2/3)O3 has been prepared by simple solid state reaction route with density >93% at relatively low sintering of 1175°C making it compatible for microwave dielectric applications. The samples are characterized by X-ray diffraction analysis and scanning electron microscopy. The X-ray diffraction shows pure perovskite phase with cubic structure. The lattice constants were obtained a = 4.1032 Å. Detailed studies of ε′ and ε′′ show that the compound exhibits dielectric anomaly at 430°C. Material shows distributed relaxation at higher temperature. Impedance analysis revealed that the impedance is mainly due to the grains. AC conduction activation energies are estimated from Arrhenius plots, and conduction mechanism is discussed.

Preparation and Characterization of Polycrystalline Cubic Boron Nitride (PcBN) Compacts by a Pressureless Sintering Process

2010 ◽  
Vol 105-106 ◽  
pp. 38-41 ◽  
Author(s):  
Zhen Huo Ren ◽  
Rui Zhang ◽  
Hai Long Wang ◽  
De Liang Chen ◽  
Ming Liang Li
Keyword(s):  
Boron Nitride ◽  
Cubic Boron Nitride ◽  
Cost Effective ◽  
Sintering Behavior ◽  
Pressureless Sintering ◽  
X Ray Diffraction ◽  
Polycrystalline Cubic Boron Nitride ◽  
Air Atmosphere ◽  
Sintering Method

A novel cost-effective pressureless sintering method has been developed to prepare polycrystalline cubic boron nitride (PcBN) compacts. The effect of feldspar as sintering aids was analyzed in this paper. Various amounts of feldspar from 5 to 15 wt% were added to cBN powders, and the pressureless sintering was conducted at temperatures ranging from 900°C to 1200°C under an air atmosphere. The microstructure, phase, density and microhardness of the as-obtained PcBN compacts were measured and correlated to amounts of Si added and to sintering temperatures. The sample showed superior sintering behavior in comparison to those fabricated using hot pressed sintering. The results of X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that feldspar diffused homogeneously and tightly bonded with cBN. But hBN appeared when the sintering temperature even at 900°C, which dramatically affected the property of PcBN compacts. A PcBN compact with a relative density of 91% was obtained at 1100°C and its microhardness was as high as 1000HV.

Magnetic Interactions Study in ZnO Doped with Fe Ions Produced by Thermal Diffusion Processes

2013 ◽  
Vol 1494 ◽  
pp. 25-30 ◽  
Author(s):  
R. Baca ◽  
M. Galván ◽  
J. V. Méndez ◽  
J. A. Andraca ◽  
R. Peña
Keyword(s):  
Diffusion Processes ◽  
Magnetic Semiconductors ◽  
Magnetic Moments ◽  
Magnetic Domain ◽  
Magnetic Ordering ◽  
Transition Metal Ions ◽  
Magnetic Interactions ◽  
Iron Ions ◽  
X Ray Diffraction ◽  
Alternating Magnetic Fields

ABSTRACTRecently, the oxides have received attention and great interest due to their magnetic ordering above of the room temperature by doping a very low amount of transition metal ions, which are very promising for applications such as biosensing, hyperthermia, doped magnetic semiconductors with lower energy losses and rapid response at alternating-magnetic fields. In this work the magnetic interactions on Fe doped ZnO thin-films was studied. Raman spectroscopy allowed the monitoring of iron ions diffusion and demonstrated that symmetry modes are crucial for understanding of the magnetic ordering. X-ray diffraction (XRD) was used to determine the oxidation state of the iron ions and stress into ZnO lattice. MFM confirmed that magnetic moments and magnetic forces on scanned surface depend on magnetic-domain structure formation.

scholarly journals Nanostructure-Related Magnetic Properties of Various Mesoporous Cobalt Oxide and Cobalt Ferrite Spinel Phases

2019 ◽  
Author(s):  
Roberto Köferstein
Keyword(s):  
Magnetic Properties ◽  
Cobalt Oxide ◽  
Cobalt Ferrite ◽  
Magnetic Ordering ◽  
Magnetic Behavior ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spinel Phases ◽  
Ferrite Spinel

Nanostructure-related magnetic properties are investigated systematically for various mesoporous cobalt oxide (Co3O4) and cobalt ferrite (CoFe2O4) spinel phases. Synthesis of thematerials by nanocasting offers the opportunity to obtain materials which are different from each other with respect to both specific surface area and crystallite size. As a result, the respective contributions of two types of interfaces, namely, “solid–gas” and “solid–solid” interfaces, to the magnetic ordering can be distinguished. Structural characterization of the porous materials by X-ray diffraction, N2 physisorption, and electron microscopy as well as investigation of the magnetic behavior (field-dependent magnetization and temperaturedependentsusceptibility) are presented.

scholarly journals Electromagnetic characterization of Ni0.5Zn0.3Co0.2Fe2O4 bulk ceramics in the 1MHz-12GHz frequency range

2021 ◽  
Vol 15 (2) ◽  
pp. 136-145
Author(s):  
Vera Lucia de Brito ◽  
Julia Maria de Morais Santos ◽  
João Paulo Machado ◽  
Cristina Bormio-Nunes ◽  
Francisco Carvalho
Keyword(s):  
Complex Permittivity ◽  
Sintered Sample ◽  
Magnetic Behaviour ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Air Atmosphere ◽  
Ferrite Sample ◽  
Complex Magnetic Permeability ◽  
Permittivity Measurements

In this paper, NiZnCo ferrite was produced by solid state synthesis, calcination at 1000?C and sintering at 1250?C in air atmosphere. The microstructure and phases of the sintered sample were analysed by scanning electron microscopy and X-ray diffraction, respectively. The magnetic properties of the ferrite were evaluated by magnetization and magnetostriction measurements. The complex magnetic permeability and complex permittivity were also measured between 1MHz-12GHz and the reflection loss (RL) was calculated in the 100MHz-12GHz frequency range. The results show that the ferrite sample presents magnetostrictive behaviour and a saturation magnetization of 71 Am2/kg. Complex permittivity measurements indicate that the material has dielectric behaviour in the whole frequency range studied, with "? varying between 7-40, and magnetic behaviour in frequencies between 1MHz-5GHz. The minimum RL was found at frequencies between 2.4-3.3GHz and the calculated RL value for a thickness of 3mm was lower than ?10 dB in frequencies between 2.3-7.3GHz. These results indicate potential application as microwave absorber in the S band.

Electrochemical Growth and Characterization of Lead Sulphide Thin Films

2013 ◽  
Vol 16 (2) ◽  
pp. 133-137
Author(s):  
S. Thanikaikarasan ◽  
T. Mahalingam ◽  
S. Veeramuthumari ◽  
Luis Ixtlilco
Keyword(s):  
Thin Films ◽  
X Rays ◽  
X Ray Diffraction ◽  
Lead Sulphide ◽  
Electrochemical Growth ◽  
Microstructural Parameters ◽  
Glass Substrates ◽  
Direct Band ◽  
Acidic Bath

Growth of lead sulphide thin films has been carried out electrochemically on indium doped tin oxide coated conducting glass substrates from an aqueous acidic bath containing Pb(CH3COO)2 and Na2S2O3. X-ray diffraction pattern showed that the deposited films possess cubic structure with most prominent reflection along (200) plane. The dependency of microstructural parameters such as crystallite size, strain and dislocation density with film thickness has been analyzed. Surface morphology and film composition have been analyzed using scanning electron microscopy and energy dispersive analysis by X-rays. Optical absorption analysis showed that the prepared films possess a direct band gap value of 0.37 eV.

Synthesis of ZnO by Mechanical Activation and Make the Varistor

2011 ◽  
Vol 110-116 ◽  
pp. 1599-1605
Author(s):  
Mahmood Reza Mehran
Keyword(s):  
Raw Materials ◽  
Sol Gel ◽  
Planetary Mill ◽  
Raw Material ◽  
Process Efficiency ◽  
X Ray Diffraction ◽  
Zno Nanopowder ◽  
Direct Band ◽  
Hydrothermal Methods

ZnO is a semiconductor with direct band gap that because of its optical and electronically properties has very interesting for researchers. Wide application of this compound in electronic and optic like piezoelectric transducer, gas sensor, optical waveguide, thin conductor layer and transparent, varistors, photocells, optical U.V. equipments and also variety medical applications with concerning its nature friendly cause that to find the economical method for mass production be concerned. During recent decay, many methods such as sol-gel, wet chemistry, CVD & MOCVD, hydrothermal methods and development process have been invented for ZnO production. The most common problems of these methods are complexity of production process, need to expensive equipments, need to expensive raw materials, need to exceedingly pressure and temperature etc. In this research with activation of Zn as the raw material, nanoparticles of ZnO has been product by a planetary mill and hydride action that this method has ability to extensile in industrial range.SEM investigations approve the nanosize of produced particles. Morphology of particles is more similar to hexagonal crystal structure. Process efficiency is 100 percent and x-ray diffraction (XRD) of resultant powder verifies this. After synthesis and characterization of ZnO nanopowder as one of its application, varistor was made and then electrical property of this part was evaluated.

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