scholarly journals Laser induced adjustment of the conductivity of rare earth doped Mn-Zn nanoferrite

2017 ◽  
Vol 35 (3) ◽  
pp. 519-527 ◽  
Author(s):  
S. I. El-Dek ◽  
M. A. Ahmed ◽  
Alaaeldin A. Eltawil
Keyword(s):  
Rare Earth ◽  
Laser Irradiation ◽  
High Resistivity ◽  
Frequency Variation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Ray Density ◽  
Ft Ir ◽  
Rare Earth Doped

AbstractTwo series of Mn-Zn nanoferrites (namely Mn1-xZnxFe2O4 and Mn1-xZnxFe2-yRyO4) were synthesized using standard ceramic technique. X-ray diffraction and FT-IR were employed in the chacterization of the nanopowder. The X-ray density for each sample increased after laser irradiation which was correlated with the decrease in the unit cell volume. The study involved the thermal and frequency variation of the dielectric constant and AC conductivity of the investigated samples before and after laser irradiation. The later altered the conductivity by decreasing its value for the rare earth doped samples except for the Sm3+ doped one. The results suggested the exploitation of Mn-Zn doped rare earth nanoferrites in many technological applications demanding high resistivity.

scholarly journals High Pressure X-ray Diffraction as a Tool for Designing Doped Ceria Thin Films Electrolytes

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 724
Author(s):  
Sara Massardo ◽  
Alessandro Cingolani ◽  
Cristina Artini
Keyword(s):  
Thin Films ◽  
High Pressure ◽  
Rare Earth ◽  
Ionic Conductivity ◽  
Bulk Material ◽  
Threshold Temperature ◽  
Doped Ceria ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rare Earth Doped

Rare earth-doped ceria thin films are currently thoroughly studied to be used in miniaturized solid oxide cells, memristive devices and gas sensors. The employment in such different application fields derives from the most remarkable property of this material, namely ionic conductivity, occurring through the mobility of oxygen ions above a certain threshold temperature. This feature is in turn limited by the association of defects, which hinders the movement of ions through the lattice. In addition to these issues, ionic conductivity in thin films is dominated by the presence of the film/substrate interface, where a strain can arise as a consequence of lattice mismatch. A tensile strain, in particular, when not released through the occurrence of dislocations, enhances ionic conduction through the reduction of activation energy. Within this complex framework, high pressure X-ray diffraction investigations performed on the bulk material are of great help in estimating the bulk modulus of the material, and hence its compressibility, namely its tolerance toward the application of a compressive/tensile stress. In this review, an overview is given about the correlation between structure and transport properties in rare earth-doped ceria films, and the role of high pressure X-ray diffraction studies in the selection of the most proper compositions for the design of thin films.

Synthesis and Luminescence Properties of Doped Magnesium Boro-Tellurite Ceramics

2015 ◽  
Vol 73 (1) ◽  
Author(s):  
Nur Zu Ira Bohari ◽  
R. Hussin ◽  
Zuhairi Ibrahim ◽  
Hendrik O. Lintang
Keyword(s):  
Rare Earth ◽  
Solid State ◽  
Solid State Reaction Method ◽  
Luminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Emission Transition ◽  
Bending Mode ◽  
Two Phases ◽  
Rare Earth Doped

Glass has been widely utilized in the field of lighting, telecommunication and spectroscopy. Boro-tellurite is one of the suitable glasses used for solid state lighting and laser application. The investigation on the luminescence properties of rare earth doped ceramic is rarely used due to the opacity. In this paper boro-tellurite prepared in ceramic can show the better luminescence with the less advantage. The aim of this paper is to present the effect and advantages in luminescence results of boro-tellurite ceramics doped with the constant amount of rare earth. Doped magnesium boro-tellurite with Eu3+ and Dy3+ ceramic have been prepared using solid state reaction method with the compositions of xTeO2-(70-x)B2O3-30MgO with 10≤x≤40, and have been doped with Eu2O3 (1mol%) and Dy2O3 (1mol%) . The characterizations of the samples have been investigated by means of X-Ray diffraction, Raman, Infrared and Photoluminescence spectroscopy. From the X-ray diffraction results, two phases are assigned to MgTe2O5 and Mg2B2O5. Raman spectroscopy showed strong bands observed in the vicinity of 140, 175, 220, 266, 332, 403, 436, 646, 694, 723, 757 and 806 cm-1. FTIR spectra showed bands located in the range between 400-800 cm-1 are assigned to the bending mode of Te-O-Te, TeO3 and TeO4. In the range of 800-1400 cm-1,the bands are associated with B-O, B-O-B, BO3 and BO4 bonds. The emission transition 5D0-7F2 corresponded to the red emission (612 nm) was found to be the most intense in all the Eu3+-doped magnesium boro-tellurite ceramics.  

Laser alloying of Cu and Cr

1986 ◽  
Vol 1 (5) ◽  
pp. 652-660 ◽  
Author(s):  
J.F.M. Westendorp ◽  
W. Koelewijn ◽  
W.G.J.H.M. van Sark ◽  
F.W. Saris ◽  
N.M. van der Pers ◽  
...  
Keyword(s):  
Laser Irradiation ◽  
Threshold Energy ◽  
Peak Shift ◽  
Laser Wavelength ◽  
Laser Alloying ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Cu Substrates ◽  
The Individual

CuCr multilayers, 0.5−1 /um total thickness, on Cu substrates have been laser irradiated. Threshold energy densities for complete alloying with different laser wavelengths and different multilayer structures were determined using Rutherford backscattering. Results are discussed in terms of absorbance of Cu and Cr as a function of laser wavelength, overall chemical composition, and thicknesses of the individual Cu and Cr layers. Also, x-ray diffraction was used to study the microstructure of the CuCr before and after laser irradiation. A method is outlined for unraveling the contributions to peak shift of stacking faults, stresses, and change in'chemical composition. The CuCr alloy produced by the laser irradiation consisted of small, very defective Cu-rich and Cr-rich crystallites. The CuCr layer was subjected to a high tensile stress. The distinct change in preferred orientation of crystallites on laser irradiation indicated a complete melting of the CuCr multilayer. A high tensile strength (> 935 MPa) of the CuCr before and after laser alloying is suggested by the microstructure as observed by x-ray diffraction and sustained by hardness measurements. In the Cu-rich crystals 4.0 at. % Cr was in solid solution, i.e., five times the maximum equilibrium solid solubility.

Magnetic properties of (Sr1.85Ln0.15)FeMoO6 with Ln = Sr, La, Ce, Pr, Nd, Sm and Eu

2011 ◽  
Vol 239-242 ◽  
pp. 3109-3112 ◽  
Author(s):  
Qin Zhang ◽  
Qing Wang ◽  
Zhen Cui Sun ◽  
Ke Yan Wang
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Ionic Radius ◽  
Single Phase ◽  
Magnetic Measurements ◽  
Rare Earth Ions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rare Earth Doped ◽  
The Eu

Rare-earth-doped compounds (Sr1.85Ln0.15)FeMoO6(Ln=Sr, La, Ce, Pr, Nd, Sm and Eu) have been prepared by solid-state reaction. Crystal structure and magnetic properties were investigated by means of X-ray diffraction and magnetic measurements. All the samples are single phase and belong to the I4/m space group. Due to the competing contributions of electron doping and steric effects, the unit-cell volume of the doped compounds changes slightly and does not vary systematically with the ionic radius of the rare-earth ions. The temperature dependence of the magnetization of (Sr1.85Ln0.15)FeMoO6indicates that the Curie temperature of the doped compounds has increased upon doping, except for the Eu-doped compound.

Preliminary Research on the Uptake Behavior of Ammonium Molybdophosphate for Cesium and the Corresponding Structural Transformation

2012 ◽  
Vol 535-537 ◽  
pp. 2191-2194 ◽  
Author(s):  
Zhao Ya Huang ◽  
Dong Zhang ◽  
Zhao Yi Tan
Keyword(s):  
Exchange Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ammonium Molybdophosphate ◽  
Before And After ◽  
Initial Ph ◽  
Negative Effect ◽  
Ft Ir ◽  
Ph Conditions ◽  
Ir And Raman

In this work, Ammonium Molybdophosphate (AMP) was synthesized and the adsorption of Cs onto it under different initial pH conditions was investigated. The results show the negative effect of the hydronium and hydroxyl irons on the uptake of Cs while the iron-exchange capacity can reach 144.8 mg/g. In addition, the structure differences between AMP samples before and after Cs adsorption were examined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Raman technique. The results show that the Keggin structure of AMP stayed unchanged while new bonds arose after the Cs adsorption.

Luminescence and X-ray Diffraction Studies of Rare Earth Doped Silica Sol-Gel Glass

2019 ◽  
Vol 25 (9) ◽  
pp. 255-262 ◽  
Author(s):  
Kurt R. Hoffman ◽  
Henok Alazar ◽  
Dan Boye ◽  
Ann Silversmith
Keyword(s):  
Rare Earth ◽  
Sol Gel ◽  
Silica Sol ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rare Earth Doped

High pressure X ray diffraction studies of rare earth doped Bi 2212 system

1999 ◽  
Author(s):  
Ravhi S. Kumar ◽  
A. Sekar ◽  
N. Victor Jaya ◽  
S. Natarajan
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rare Earth Doped

Preparation and Properties of Rare Earth-Doped TiO2 Thin Films by Sol-Gel Process

2014 ◽  
Vol 1033-1034 ◽  
pp. 1235-1238
Author(s):  
Tao Bai ◽  
Shi Gen Zhu
Keyword(s):  
Thin Films ◽  
Rare Earth ◽  
Sol Gel ◽  
Rare Earth Doping ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process ◽  
Scanning Electronmicroscopy ◽  
Rare Earth Doped ◽  
The Rare Earth

Rare earth doped titaniumdioxide (TiO2) thin films (rare earth-doped TiO2) have been successfully prepared on a glass substrate by a sol–gel route. After the rare earth-doped TiO2thin films were calcined at 773K for 1h, the effect of rare earth-doping on the properties were investigated using X-ray diffraction (XRD), scanning electronmicroscopy (SEM), ultraviolet–visible spectroscopy and thermogravimetric techniques (TG/DTG). The XRD results showed that rare earth-doped TiO2thin films contained only a single crystalline phase of anatase TiO2after calcining at 773K for 1h. SEM micrographs showed that rare earth-doped TiO2thin films have smooth surfaces containing granular nanocrystallines and are without cracks. The UV–vis absorption spectra showed that the absorption of the rare earth-doped TiO2thin films has a red-shift. From ambient to 1273K, it is about 12% of mass loss because of the volatilizing of water and organic and the phase transformation.

scholarly journals Ion exchange of sodium with hydrochloric acid in ZSM-5 zeolite

2021 ◽  
Vol 62 (3) ◽  
pp. 155-165
Author(s):  
Milomirka Škrba ◽  
Zoran Obrenović ◽  
Aleksandar Došić ◽  
Miladin Gligorić ◽  
Biljana Đurić ◽  
...  
Keyword(s):  
Hydrochloric Acid ◽  
Ion Exchange ◽  
Sodium Content ◽  
Sem Analysis ◽  
Hydrogen Ions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Exchange Time ◽  
Before And After ◽  
Ft Ir

ZSM-5 zeolites are highly silicate materials that have significant application in catalytic processes in petrochemistry, especially due to their high selectivity. Most reactions in the petrochemical industry are acid-catalyzed. The acidic properties of zeolite depend on the number of acid centers, i.e. the presence of hydrogen ions, and therefore, in this paper the possibility of reducing the sodium content in the pores of high silicate zeolite ZSM-5 with the modulus (SiO2 / Al2O3 = 1000) will be investigated, by applying ion exchange with hydrochloric acid. Chemical analysis of samples before and after ion exchange, and application of instrumental methods of X-Ray diffraction, FT-IR spectroscopy, and SEM analysis monitored the influence of the quantity of hydrogen ions on the chemical composition and the structure of ZSM-5 zeolite at different acid concentrations and at different exchange times. It has been shown that the application of ion exchange with hydrochloric acid can reduce the sodium content in zeolite. Even with the application of 5% HCl for 6 hours, the content of sodium in the zeolite is reduced by over 98%. A similar effect is achieved by applying more concentrated hydrochloric acid solutions for a shorter ion exchange time. By prolonging the ion exchange time, there are no significant changes in terms of the final ion exchange. On the other hand, the application of HCl solutions of higher concentrations leads to a slight decrease in the aluminum content in the zeolite, which may partially affect the structural stability of the zeolite. The results obtained by FT-IR and SEM analysis and X-Ray diffraction confirm the possibility of ion exchange with hydrochloric acid, without significant changes in the crystal structure of the zeolite.

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