Madani Samah - Academia.edu (original) (raw)

Papers by Madani Samah

Research paper thumbnail of Blue and yellow luminescence of GaN nanocrystals-doped SiO2 matrix

Physica E: Low-dimensional Systems and Nanostructures, 2008

GaN-SiO 2 nanocomposite and GaN-free nanopowder are studied. X-ray diffraction (XRD), transmissio... more GaN-SiO 2 nanocomposite and GaN-free nanopowder are studied. X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL) and photoluminescence electron excitation (PLE) techniques are used to investigate their structural and optical properties. Microstructural study reveals flattened sphere-like crystallites with a mean size of around 150 nm in the GaN-SiO 2 sample, and multimodal size distributions in the raw GaN powder. A strong yellow and blue luminescence centred at 2.25and2.25 and 2.25and2.9 eV, respectively, is observed in the room-temperature PL spectra of the nanocomposite with the one of the powder. Ambient PLE measurements reveal several zero-phonon lines of the YL line, which lead to several type defects. The optical measurements are correlated with structural defects such as (V Ga-O N) 2À , (V Ga-O 2N) 1À and surface defects.

Research paper thumbnail of Intense photoluminescence of slightly doped ZnO–SiO2 matrix

Chemical Physics Letters, 2006

ZnO nanocrystals are embedded in an amorphous matrix of SiO 2 using the sol-gel method and their ... more ZnO nanocrystals are embedded in an amorphous matrix of SiO 2 using the sol-gel method and their optical properties were studied. A strong Blue-violet luminescence was observed. The photoluminescence's maximum, located at 400 nm approximately, depends on the rate of the gelation process and also shows a slight dependence with the wavelength of excitation. The mean size of ZnO particles is about 27 nm leading with a weak quantum confinement. XRD patterns did not reveal the presence of ZnO particles but TEM investigation demonstrates agglomeration of ZnO crystallites in the composite with different sizes and shapes.

Research paper thumbnail of Optical properties of ZnO aggregates in KBr matrix

Semiconductor Physics, Quantum Electronics and Optoelectronics, 2003

Zinc oxide nanocrystals were prepared, using Czochralski method of growth, in KBr matrix during p... more Zinc oxide nanocrystals were prepared, using Czochralski method of growth, in KBr matrix during pulling. Good evidences can prove that the quantum confinement effect is the special quality for this nanosystem. As an indication of quantum confinement effect, excellent emissions from band edge have been observed in optical absorption spectra and on selective PL ones. CL spectrum exhibits several levels in band gap allotted to different types of impurities in matrix and within ZnO aggregates.

Research paper thumbnail of Ab initio study of structural, electronic and magnetic properties of iron clusters Fen (n=2-13)

Revista Mexicana De Fisica, 2011

Structures, binding energies, and magnetic moments of Fen (n = 2–13) clusters have been obtained ... more Structures, binding energies, and magnetic moments of Fen (n = 2–13) clusters have been obtained by pseudopotential density functional theory. A Troullier-Martin scheme was used to generate the iron’s pseudopotential and we have successfully reproduced results (lattice constant and magnetic moment) for the bulk BCC iron. The results indicate that the magnetic moment per atom varies slowly around a mean value 3.0 μB/atom. With increasing atom number the mean binding energy monotonically decreases.

Research paper thumbnail of Quantum transport properties of gas molecules adsorbed on Fe doped armchair graphene nanoribbons: A first principle study

Graphene, when doped with transition metals, is considered, both experimentally and theoretically... more Graphene, when doped with transition metals, is considered, both experimentally and theoretically, as a good candidate for the detection of gas molecules as CO, CO2, NO or NO2. This opens new perspectives for gas sensor set-ups considering that devices based on 2 dimensional graphene are more sensitive to detect molecules than solid-state gas sensors. The state of the arts on gas adsorption on Fe doped armchair graphene nanoribbons (Fe-AGNR) is still in its starting phase and thorough investigations of the mechanism of the adsorption on graphene need to be done. In the present work, the electronic and transport properties of molecules adsorbed on Fe-AGNR are scrutinized using ab-initio calculations. We observe that the adsorption of gas molecules on Fe-AGNR changes significantly the electronic properties of both the valence and the conduction band. Besides, The adsorbed molecules change the local electron density of states of the graphene nanoribbons, modifying thus the conductivity...

Research paper thumbnail of Density Functional Theory Study of Gold Doped Armchair Graphene Nanoribbons with Vacancies

Journal of Computational and Theoretical Nanoscience

Research paper thumbnail of Effect of Vacancies on Electronic and Magnetic Properties of Hydrogen Passivated Graphene Nanoribbons

Acta Physica Polonica A

Using first-principles calculations we have demonstrated that electronic and magnetic properties ... more Using first-principles calculations we have demonstrated that electronic and magnetic properties of armchair graphene nanoribbons are modified by introducing vacancies defects. The equilibrium geometries, electronic, charge spin density distributions, electronic band structures, and magnetic moments were examined in the presence of vacancies. We have found that introducing vacancies into armchair graphene nanoribbons changes the spatial distribution of neighbor atoms, particularly those located around the vacancies. Our calculations showed that the vacancies have significant effect on the magnetization of armchair graphene nanoribbons. Magnetic moment values and electronic behavior in different configurations depend on the number of vacancies. These results suggest that vacancy defects can be used to modify the electronic and the magnetic properties of armchair graphene nanoribbons.

Research paper thumbnail of Propri�t�s optiques et structurales des agr�gats de bromure d'argent dans une matrice ionique

Research paper thumbnail of Effect of nitrogen impurities on the physical properties of ZnO nanowires: First-principles study

Physical Review B, 2012

ABSTRACT

Research paper thumbnail of Electronic and magnetic properties of ring-like Fe 6 and Fe 6@Si 12 clusters

Physics Letters A, 2005

Novel structures based on Fe atoms encapsulated within a Si12 cluster are studied. Electronic and... more Novel structures based on Fe atoms encapsulated within a Si12 cluster are studied. Electronic and magnetic properties of ring-like Fe6 and Fe6@Si12 were investigated using the frame work of density functional theory (DFT). We have demonstrated that Si12 cluster can be stabilized by encapsulating transition metal atoms (TMAs), Fe atoms. The magnetic moment of free Fe6 cluster is of 3.67μB,

Research paper thumbnail of STRUCTURES, ELECTRONIC AND MAGNETIC PROPERTIES OF C 20 FULLERENES DOPED TRANSITION METAL ATOMS M@ C 20 (M= Fe, Co, Ti, V)

International Journal of Modern Physics C, 2010

... A 111, 10439 (2007). 17. H. Stoll and A. Savin, Density Functional Methods in Physics, eds. R... more ... A 111, 10439 (2007). 17. H. Stoll and A. Savin, Density Functional Methods in Physics, eds. RM Dreeizler and JD Providentia, NATO-ASI Series (Netherland, 1985), p. 177. 18. E. Rubén, REEstrada-Salas and AA Valladares, J. Mol. Struct. (THEOCHEM) 869, 1 (2008). 19. ...

Research paper thumbnail of CuCl Nanocrystals in Monocrystalline NaCl Matrix

Physica Scripta, 2004

It is demonstrated that the growth of CuC1 crystals in a single crystal of NaC1 can be realized b... more It is demonstrated that the growth of CuC1 crystals in a single crystal of NaC1 can be realized by the doping of the melted NaCl solution with copper. The absorption spectra in ambient exhibit peaks allotted to the excitonic transitions with a displacement towards great energies. The mean size of the crystallites is approximately 20 Å. From absorption spectra analysis, it was also shown that the heat treatments lead to an increase of the size of the CuCl particles. X-ray diffraction patterns demonstrate the good crystallinity of the matrix as well as the presence of CuCl in this matrix.

Research paper thumbnail of DFT based study of Aun(4–7) clusters: new stabilized geometries

Physica Scripta, 2007

ABSTRACT

Research paper thumbnail of Ab Initio Study of Structural Stability and Magnetic Properties of Con(n = 2 - 10):. a Study Based on Pseudopotentials DFT

International Journal of Modern Physics C - IJMPC, 2011

The lowest-energy geometric and isomers of freestanding Con clusters (n = 2 - 10) and their corre... more The lowest-energy geometric and isomers of freestanding Con clusters (n = 2 - 10) and their corresponding magnetic moments have been studied using the Siesta code based on pseudopotential density-functional theory. The calculated results show that there are many isomers near the ground state. Different isomers hold different magnetic moment. The stability study shows that among the investigated clusters, the hexamer one is the most stable and is the magic cluster. Dissociation channels energy are also studied.

Research paper thumbnail of Optical responses of alkali-halide matrix (NaCl)-doped silver

Physica E-low-dimensional Systems & Nanostructures, 2004

In this work, we investigated the optical properties and the evolution of AgCl semiconductor aggr... more In this work, we investigated the optical properties and the evolution of AgCl semiconductor aggregates dispersed in an ionic crystalline matrix, NaCl. These aggregates were obtained by doping the NaCl matrix with a silver powder (Ag). Microcrystals of AgCl of various sizes were consequently obtained with a mean size of 30Å. A thermal annealing, whose principal effect is the variation

Research paper thumbnail of Non-linear emissions of MOVPE ZnSe epilayers

… Science and Engineering: …, 2006

Non-linear photoluminescence emissions of n-type ZnSe epitaxial layers grown by MOVPE have been s... more Non-linear photoluminescence emissions of n-type ZnSe epitaxial layers grown by MOVPE have been studied at low temperature. The processes involved in the spectra of photoluminescence in highly excited ZnSe epilayers are assumed to be a combination of ...

Research paper thumbnail of Propriétés optiques et structurales des agrégats de bromure d'argent dans une matrice ionique

Annales de Chimie Science des Matériaux, 2004

Dans ce travail, nous nous sommes interesses a l'etude des proprietes optiques et a l'evo... more Dans ce travail, nous nous sommes interesses a l'etude des proprietes optiques et a l'evolution des agregats de semi-conducteurs de AgBr disperses dans une matrice cristalline ionique, KBr. Ces agregats sont elabores par le dopage d'une matrice KBr avec une poudre d'argent. Des microcristaux de AgBr de differentes tailles sont par consequent obtenus. On a procede ensuite a des recuits thermiques, ayant comme principal effet une variation des tailles des cristallites. Cette etude a ete menee d'une maniere systematique par des mesures d'absorption optique, de diffraction des rayons X (DRX) et de photoluminescence. Une relation entre la taille des microcristaux et le deplacement des pics d'absorption vers les basses energies est mise en evidence. L'absorption optique et la photoluminescence nous montrent la presence des agregats de bromure d'argent ainsi que leur photosensibilite traduite par la formation d'agregats d'argent.

Research paper thumbnail of Structure and electronic property of medium-sized silicon clusters

Physica E-low-dimensional Systems & Nanostructures, 2006

The lowest energy structures of Sin (n=10–20) clusters are obtained using the first principles ps... more The lowest energy structures of Sin (n=10–20) clusters are obtained using the first principles pseudopotential simulated annealing within the local density functional approximation (LDA) implemented in SIESTA method. New low-energy structures are obtained for each cluster size. The Sin clusters generally follow a prolate structures for n16 and, like spherical structures, with the appearance of an endohedral atom with highly

Research paper thumbnail of Structural, morphological and steady state photoluminescence spectroscopy studies of red Eu(3+) -doped Y2 O3 nanophosphors prepared by the sol-gel method

Luminescence : the journal of biological and chemical luminescence, Jan 31, 2015

Europium trivalent (Eu(3+) )-doped Y2 O3 nanopowders of different concentrations (0.5, 2.5, 5 or ... more Europium trivalent (Eu(3+) )-doped Y2 O3 nanopowders of different concentrations (0.5, 2.5, 5 or 7 at.%) were synthesized by the sol-gel method, at different pH values (pH 2, 5 or 8) and annealing temperatures (600°C, 800°C or 1000°C). The nanopowders samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR) and steady state photoluminescence spectroscopy. The effect of pH of solution and annealing temperatures on structural, morphological and photoluminescence properties of Eu(3+) -doped Y2 O3 were studied and are discussed. It was found that the average crystallite size of the nanopowders increased with increasing pH and annealing temperature values. The Y2 O3 :Eu(3+) material presented different morphology and its evolution depended on the pH value and the annealing temperature. Activation energies at different pH values were determined and are discussed. Under ultraviolet (UV) ligh...

Research paper thumbnail of Magnetic properties of Fe2n and (FePt) n (n<= 5) clusters and magnetic anisotropy of transition metal dimers

… Magnetism and Magnetic …, 2010

... doi:10.1016/j.jmmm.2010.06.040 | How to Cite or Link Using DOI Copyright © 2010 Elsevier BV A... more ... doi:10.1016/j.jmmm.2010.06.040 | How to Cite or Link Using DOI Copyright © 2010 Elsevier BV All rights reserved. Permissions &amp; Reprints. Magnetic properties of Fe 2n and (FePt) n (n≤5) clusters and magnetic anisotropy of transition metal dimers. ...

Research paper thumbnail of Blue and yellow luminescence of GaN nanocrystals-doped SiO2 matrix

Physica E: Low-dimensional Systems and Nanostructures, 2008

GaN-SiO 2 nanocomposite and GaN-free nanopowder are studied. X-ray diffraction (XRD), transmissio... more GaN-SiO 2 nanocomposite and GaN-free nanopowder are studied. X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL) and photoluminescence electron excitation (PLE) techniques are used to investigate their structural and optical properties. Microstructural study reveals flattened sphere-like crystallites with a mean size of around 150 nm in the GaN-SiO 2 sample, and multimodal size distributions in the raw GaN powder. A strong yellow and blue luminescence centred at 2.25and2.25 and 2.25and2.9 eV, respectively, is observed in the room-temperature PL spectra of the nanocomposite with the one of the powder. Ambient PLE measurements reveal several zero-phonon lines of the YL line, which lead to several type defects. The optical measurements are correlated with structural defects such as (V Ga-O N) 2À , (V Ga-O 2N) 1À and surface defects.

Research paper thumbnail of Intense photoluminescence of slightly doped ZnO–SiO2 matrix

Chemical Physics Letters, 2006

ZnO nanocrystals are embedded in an amorphous matrix of SiO 2 using the sol-gel method and their ... more ZnO nanocrystals are embedded in an amorphous matrix of SiO 2 using the sol-gel method and their optical properties were studied. A strong Blue-violet luminescence was observed. The photoluminescence's maximum, located at 400 nm approximately, depends on the rate of the gelation process and also shows a slight dependence with the wavelength of excitation. The mean size of ZnO particles is about 27 nm leading with a weak quantum confinement. XRD patterns did not reveal the presence of ZnO particles but TEM investigation demonstrates agglomeration of ZnO crystallites in the composite with different sizes and shapes.

Research paper thumbnail of Optical properties of ZnO aggregates in KBr matrix

Semiconductor Physics, Quantum Electronics and Optoelectronics, 2003

Zinc oxide nanocrystals were prepared, using Czochralski method of growth, in KBr matrix during p... more Zinc oxide nanocrystals were prepared, using Czochralski method of growth, in KBr matrix during pulling. Good evidences can prove that the quantum confinement effect is the special quality for this nanosystem. As an indication of quantum confinement effect, excellent emissions from band edge have been observed in optical absorption spectra and on selective PL ones. CL spectrum exhibits several levels in band gap allotted to different types of impurities in matrix and within ZnO aggregates.

Research paper thumbnail of Ab initio study of structural, electronic and magnetic properties of iron clusters Fen (n=2-13)

Revista Mexicana De Fisica, 2011

Structures, binding energies, and magnetic moments of Fen (n = 2–13) clusters have been obtained ... more Structures, binding energies, and magnetic moments of Fen (n = 2–13) clusters have been obtained by pseudopotential density functional theory. A Troullier-Martin scheme was used to generate the iron’s pseudopotential and we have successfully reproduced results (lattice constant and magnetic moment) for the bulk BCC iron. The results indicate that the magnetic moment per atom varies slowly around a mean value 3.0 μB/atom. With increasing atom number the mean binding energy monotonically decreases.

Research paper thumbnail of Quantum transport properties of gas molecules adsorbed on Fe doped armchair graphene nanoribbons: A first principle study

Graphene, when doped with transition metals, is considered, both experimentally and theoretically... more Graphene, when doped with transition metals, is considered, both experimentally and theoretically, as a good candidate for the detection of gas molecules as CO, CO2, NO or NO2. This opens new perspectives for gas sensor set-ups considering that devices based on 2 dimensional graphene are more sensitive to detect molecules than solid-state gas sensors. The state of the arts on gas adsorption on Fe doped armchair graphene nanoribbons (Fe-AGNR) is still in its starting phase and thorough investigations of the mechanism of the adsorption on graphene need to be done. In the present work, the electronic and transport properties of molecules adsorbed on Fe-AGNR are scrutinized using ab-initio calculations. We observe that the adsorption of gas molecules on Fe-AGNR changes significantly the electronic properties of both the valence and the conduction band. Besides, The adsorbed molecules change the local electron density of states of the graphene nanoribbons, modifying thus the conductivity...

Research paper thumbnail of Density Functional Theory Study of Gold Doped Armchair Graphene Nanoribbons with Vacancies

Journal of Computational and Theoretical Nanoscience

Research paper thumbnail of Effect of Vacancies on Electronic and Magnetic Properties of Hydrogen Passivated Graphene Nanoribbons

Acta Physica Polonica A

Using first-principles calculations we have demonstrated that electronic and magnetic properties ... more Using first-principles calculations we have demonstrated that electronic and magnetic properties of armchair graphene nanoribbons are modified by introducing vacancies defects. The equilibrium geometries, electronic, charge spin density distributions, electronic band structures, and magnetic moments were examined in the presence of vacancies. We have found that introducing vacancies into armchair graphene nanoribbons changes the spatial distribution of neighbor atoms, particularly those located around the vacancies. Our calculations showed that the vacancies have significant effect on the magnetization of armchair graphene nanoribbons. Magnetic moment values and electronic behavior in different configurations depend on the number of vacancies. These results suggest that vacancy defects can be used to modify the electronic and the magnetic properties of armchair graphene nanoribbons.

Research paper thumbnail of Propri�t�s optiques et structurales des agr�gats de bromure d'argent dans une matrice ionique

Research paper thumbnail of Effect of nitrogen impurities on the physical properties of ZnO nanowires: First-principles study

Physical Review B, 2012

ABSTRACT

Research paper thumbnail of Electronic and magnetic properties of ring-like Fe 6 and Fe 6@Si 12 clusters

Physics Letters A, 2005

Novel structures based on Fe atoms encapsulated within a Si12 cluster are studied. Electronic and... more Novel structures based on Fe atoms encapsulated within a Si12 cluster are studied. Electronic and magnetic properties of ring-like Fe6 and Fe6@Si12 were investigated using the frame work of density functional theory (DFT). We have demonstrated that Si12 cluster can be stabilized by encapsulating transition metal atoms (TMAs), Fe atoms. The magnetic moment of free Fe6 cluster is of 3.67μB,

Research paper thumbnail of STRUCTURES, ELECTRONIC AND MAGNETIC PROPERTIES OF C 20 FULLERENES DOPED TRANSITION METAL ATOMS M@ C 20 (M= Fe, Co, Ti, V)

International Journal of Modern Physics C, 2010

... A 111, 10439 (2007). 17. H. Stoll and A. Savin, Density Functional Methods in Physics, eds. R... more ... A 111, 10439 (2007). 17. H. Stoll and A. Savin, Density Functional Methods in Physics, eds. RM Dreeizler and JD Providentia, NATO-ASI Series (Netherland, 1985), p. 177. 18. E. Rubén, REEstrada-Salas and AA Valladares, J. Mol. Struct. (THEOCHEM) 869, 1 (2008). 19. ...

Research paper thumbnail of CuCl Nanocrystals in Monocrystalline NaCl Matrix

Physica Scripta, 2004

It is demonstrated that the growth of CuC1 crystals in a single crystal of NaC1 can be realized b... more It is demonstrated that the growth of CuC1 crystals in a single crystal of NaC1 can be realized by the doping of the melted NaCl solution with copper. The absorption spectra in ambient exhibit peaks allotted to the excitonic transitions with a displacement towards great energies. The mean size of the crystallites is approximately 20 Å. From absorption spectra analysis, it was also shown that the heat treatments lead to an increase of the size of the CuCl particles. X-ray diffraction patterns demonstrate the good crystallinity of the matrix as well as the presence of CuCl in this matrix.

Research paper thumbnail of DFT based study of Aun(4–7) clusters: new stabilized geometries

Physica Scripta, 2007

ABSTRACT

Research paper thumbnail of Ab Initio Study of Structural Stability and Magnetic Properties of Con(n = 2 - 10):. a Study Based on Pseudopotentials DFT

International Journal of Modern Physics C - IJMPC, 2011

The lowest-energy geometric and isomers of freestanding Con clusters (n = 2 - 10) and their corre... more The lowest-energy geometric and isomers of freestanding Con clusters (n = 2 - 10) and their corresponding magnetic moments have been studied using the Siesta code based on pseudopotential density-functional theory. The calculated results show that there are many isomers near the ground state. Different isomers hold different magnetic moment. The stability study shows that among the investigated clusters, the hexamer one is the most stable and is the magic cluster. Dissociation channels energy are also studied.

Research paper thumbnail of Optical responses of alkali-halide matrix (NaCl)-doped silver

Physica E-low-dimensional Systems & Nanostructures, 2004

In this work, we investigated the optical properties and the evolution of AgCl semiconductor aggr... more In this work, we investigated the optical properties and the evolution of AgCl semiconductor aggregates dispersed in an ionic crystalline matrix, NaCl. These aggregates were obtained by doping the NaCl matrix with a silver powder (Ag). Microcrystals of AgCl of various sizes were consequently obtained with a mean size of 30Å. A thermal annealing, whose principal effect is the variation

Research paper thumbnail of Non-linear emissions of MOVPE ZnSe epilayers

… Science and Engineering: …, 2006

Non-linear photoluminescence emissions of n-type ZnSe epitaxial layers grown by MOVPE have been s... more Non-linear photoluminescence emissions of n-type ZnSe epitaxial layers grown by MOVPE have been studied at low temperature. The processes involved in the spectra of photoluminescence in highly excited ZnSe epilayers are assumed to be a combination of ...

Research paper thumbnail of Propriétés optiques et structurales des agrégats de bromure d'argent dans une matrice ionique

Annales de Chimie Science des Matériaux, 2004

Dans ce travail, nous nous sommes interesses a l'etude des proprietes optiques et a l'evo... more Dans ce travail, nous nous sommes interesses a l'etude des proprietes optiques et a l'evolution des agregats de semi-conducteurs de AgBr disperses dans une matrice cristalline ionique, KBr. Ces agregats sont elabores par le dopage d'une matrice KBr avec une poudre d'argent. Des microcristaux de AgBr de differentes tailles sont par consequent obtenus. On a procede ensuite a des recuits thermiques, ayant comme principal effet une variation des tailles des cristallites. Cette etude a ete menee d'une maniere systematique par des mesures d'absorption optique, de diffraction des rayons X (DRX) et de photoluminescence. Une relation entre la taille des microcristaux et le deplacement des pics d'absorption vers les basses energies est mise en evidence. L'absorption optique et la photoluminescence nous montrent la presence des agregats de bromure d'argent ainsi que leur photosensibilite traduite par la formation d'agregats d'argent.

Research paper thumbnail of Structure and electronic property of medium-sized silicon clusters

Physica E-low-dimensional Systems & Nanostructures, 2006

The lowest energy structures of Sin (n=10–20) clusters are obtained using the first principles ps... more The lowest energy structures of Sin (n=10–20) clusters are obtained using the first principles pseudopotential simulated annealing within the local density functional approximation (LDA) implemented in SIESTA method. New low-energy structures are obtained for each cluster size. The Sin clusters generally follow a prolate structures for n16 and, like spherical structures, with the appearance of an endohedral atom with highly

Research paper thumbnail of Structural, morphological and steady state photoluminescence spectroscopy studies of red Eu(3+) -doped Y2 O3 nanophosphors prepared by the sol-gel method

Luminescence : the journal of biological and chemical luminescence, Jan 31, 2015

Europium trivalent (Eu(3+) )-doped Y2 O3 nanopowders of different concentrations (0.5, 2.5, 5 or ... more Europium trivalent (Eu(3+) )-doped Y2 O3 nanopowders of different concentrations (0.5, 2.5, 5 or 7 at.%) were synthesized by the sol-gel method, at different pH values (pH 2, 5 or 8) and annealing temperatures (600°C, 800°C or 1000°C). The nanopowders samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR) and steady state photoluminescence spectroscopy. The effect of pH of solution and annealing temperatures on structural, morphological and photoluminescence properties of Eu(3+) -doped Y2 O3 were studied and are discussed. It was found that the average crystallite size of the nanopowders increased with increasing pH and annealing temperature values. The Y2 O3 :Eu(3+) material presented different morphology and its evolution depended on the pH value and the annealing temperature. Activation energies at different pH values were determined and are discussed. Under ultraviolet (UV) ligh...

Research paper thumbnail of Magnetic properties of Fe2n and (FePt) n (n<= 5) clusters and magnetic anisotropy of transition metal dimers

… Magnetism and Magnetic …, 2010

... doi:10.1016/j.jmmm.2010.06.040 | How to Cite or Link Using DOI Copyright © 2010 Elsevier BV A... more ... doi:10.1016/j.jmmm.2010.06.040 | How to Cite or Link Using DOI Copyright © 2010 Elsevier BV All rights reserved. Permissions &amp; Reprints. Magnetic properties of Fe 2n and (FePt) n (n≤5) clusters and magnetic anisotropy of transition metal dimers. ...