Volume 5, Part 1 article 1
Magnetic properties of M2P4O12 ( M = Ni, Co, Cu)
M. Belaïchea, M.Bakhachea, M. Drillonb, A. Deroryb, J-P Lambourb
We have discussed thermodynamic properties from susceptibilities and specific heat mesurements of isostructural one-dimensional M2P4O12 system. The compounds show different magnetic behaviours, varied from ferromagnetic to antiferromagnetic ordering.
a Laboratoire de Magnétisme, Matériaux Magnétiques, Micro-onde et
Céramique. Ecole Normale Supérieure, BP 9235. Océan. Rabat. Maroc.
b Institut de Physique et de Chimie de Strasbourg. Groupe des
Matériaux Inorganiques, Rue Loes 23, 67037 Strasbourg, France.
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Volume 5, Part 1 article 2
A
Numerical anlysis of
Resin Transfer Molding
R. Ab oulaicha, S. Boujenab, J. Pousinc
The aim of this work is to study a mathematical model, based on the pseudo-concentration function model, for the filling of shallow molds with polymers. The proposed model is 2-D, the chemical reactivity of the fluid is accounted with the conversion rate satisfying a Kamal-Sourour model, and the temperature is not considered. We prove the existence of a solution of the proposed mathematical model.
a- Ecole Mohammadia d’ingénieurs,
Laboratoire d’Etude et de Recherche en Mathématiques Appliquées, B.P
765, Rabat-Agdal, Maroc
b- Universit´e Hassan
II, Facult´e des sciences Ain-Chok, B.P 5366
Maˆarif Casablanca MAROC
c- Mathematical model ling and scientific computing
Laboratory, UMR CNRS 5585,
National Institute of Applied Sciences in Lyon, 20 av. Einstein,
F-69621 Vil leurbanne Cedex France
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Volume 5, Part 1 article 3
Phase Diagram of
Ferrimagnetic System with Triangular Symmetry: Spin and
Anisotropy Effects
M. Aouzi and M. El Hafidi
The magnetic properties (phase diagram and magnetization) of a ferrimagnetic system, consisting of two magnetic sublattices (A and B ) with different spins (SA = ½ and SB = ½ ) and different inter-actions coupling together, are investigated within the framework of the effective -field theory with correlations. Furthermore, each considered sublattice has in-plane triangular symmetry requiring a coordination number of magnetic atoms z = 6 which may affect the general magnetic behavior of the system.
The effects of crystal-field interaction DB in the sublattice B (with SB i 1/2) on the magnetic properties are examined in detail. Because of the higher coordination number and different kinds of interactions acting on the system of spins, we find a number of interesting phenomena: (i) the temperature dependence of the total magnetization shows many characteristic behaviors depending on DB and SB, (ii) the presence of compensation points is conditioned by the given values of different parameters while the second order transition temperatures are studied according to each specific circumstance. The aspects of interest in this study is mainly the higher coordination number of magnetic species and the realistic interactions which are taken into account. This model can be relevant for understanding the magnetic behaviors of the new class of lamellar oxides AMO2 (A = Li, Na, Na,..; M = Ni, Fe, Co,..).
PACS numbers: 75.10.-b ; 75.10.Jm ; 75.10.Jm ;75.50.Gg
Laboratoire de
Magnétisme & de Physique des Matériaux, Faculté des Sciences Ben
M’sik, Morocco
Département de Physique, B.P 7955, Casablanca 20453, Morocco
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Volume 5, Part 1 article 4
Critical
Properties and Exchange Interactions of
Antiferromagnetic A-spinel Lattice: A Study Through
High-temperature Series Expansions
M. Hamedouna,* , H. Bakrima , A. Hourmatallaha,b and N. Benzakoura
We derive high- temperature series expansions for the spin correlation functions of the A-spinel lattice. The development is extended to the order 6 in β = 1/KBT with nearest-neighbour and next-nearest neighbour interactions. The results are given for various neighbour correlation functions (up to the third). The behaviour with the temperature is presented. The critical region is studied by applying the Padé approximants method to the corresponding high- temperature series expansion of the magnetic susceptibility and the correlation length. The approach is applied to the experimental results of the particular system A-spinel CoCo2O4 . The following estimates are obtained for the familiar critical exponents: γ = 1.382±0.010 and ν = 0.701±0.012.
a- Laboratoire de Physique du Solide, Université Sidi
Mohammed Ben Abdellah, Faculté des sciences Dhar Mahraz,
BP1796, Fes, Morocco.
b- Equipe de Physique du Solide , Ecole Normale
Supérieure, B. P 5206, Bensouda, Fes, Morocco.
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Volume 5, Part 1 article 5
THEORETICAL INVESTIGATION OF THE LEVEL ENERGIES FOR IDEAL Ga AND As VACANCIES IN GaAs
Z. El achheba
, A. Hourmatallaha,b,*
, M. Barnoussib,
N. Benzakoura
and A. Jorioa
The bound state energies of ideal Ga and As vacancies in GaAs have been studied in the Green’s-function framework in conjunction the tight-binding method. Using existing data for band structures, the Koster-Slater parameters have been estimated, the energy levels at critical points and the density of states in perturbed and unperturbed crystal have been calculated. The unrelaxed vacancy of Ga and As introduces bound state at 0.05 eV and 1.46 eV respectively above the valence band edge. These results provide justification to experimental data based on irradiation of GaAs by energetic neutrons.
a: Laboratoire de Physique du solide,
Facultés des sciences Dhar Mehraz , B.P1796
Atlas Fés Morocco
b: Laboratoire de Physique du Solide, Ecole
normale Supérieure de Fés, Bensouda, B.P 5206
Fès Morocco
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Volume 5, Part 1 article 6
Interface state
degradation of metal/ ultra-thin
oxide/semiconductor structures
under electron injections at high field
K. Kassmi and R. Maimouni
In this paper we analyze the interface state of the metal/ ultra thin oxide/ semiconductor structures and their degradation under an electrons injection from the metal or the semiconductor, by Fowler-Nordheim effect, at high electric field (> 10 MV/ cm). The metal used is chromium and the oxide layer thickness is in the range of 60Å-130Å. Before injection the energy distribution of the interface state in the semiconductor gap present a peak of energy of 0.25eV above the semiconductor valence band edge. The peak density (Nssmax) decreases with the oxide thickness. After injection the degradation of the Nssmax density depends on the oxide thickness, and increases with injected charge independently on the injected field and the polarization mode (V<0, V>0) of the structure for the high injected charge (Qinj > 2 10-1 c/cm2 ). The injection influence on the interface state density (Nssmid) at mid gap is not important. The Nssmid density is lower than 1010 eV-1 cm-2 for all the injection charges (V<0, V>0). Also, we showed that the sensitivity to the degradation by electrons injection decreases with the oxide thickness. In comparing with the literature results we deduced a lower interface state density on our structures, and a satisfactory sensitivity to the degradation to high injecting fields.
PACS : 73.40.Qv, Metal-insulator-semiconductor structures (including semiconductor-to-insulator).urn.
Laboratoire d'Electronique Appliquée et
d'Automatique L.E.A.A, Université Mohamed
Premier, Faculté des Sciences, Dépt de
Physique, Route Sidi Maafa BP 524 Oujda,
Morocco
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Volume 5, Part 1 article 7
Combination of
theoretical analysis
and FTIR to study
the photocurrent oscillation
of Silicon in fluoride media
F. Yahyaoui1 , L. Hlou2 , M. Aggour1,*
To deepening our knowledge of the behaviour of the silicon/electrolyte interface, a study of photocurrent oscillations on silicon in fluoride concentration c F =0.033 M is realized, and as a confirmation of the result the investigation is extrapolated to a variety of electrolyte compositions. The etch rates of anodic oxides in diluted fluoride solutions have been determined by using a new approach of the analysis of anodic current oscillations. The time dependent thickness of the anodic oxide has been measured by in-situ FTIR and can be simulated considering only the time dependent current and the etch rate.
1 Département de Physique - LPMC - Faculté
des Sciences, B.P 133, 14000, Kénitra –
Morocco
2 Département de Physique - LTNPSA -
Faculté des Sciences B.P 133, 14000,
Kénitra –
Morocco
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Volume 5, Part 1 article 8
Relativistic analyse of extended norm-conserving pseudo-potentials
Mounir NEJJAR * and Ahmed QACHAOU
Extended norm-conserving pseudopotentials developed by E. L. Shirley et al. [1] in non relativistic case, is obtained in present work in the relativistic case. We discuss the importance of the added relativistic terms and we carry out a test of this new extension on some transition-metal atoms. This correction enables us to adapt norm-conserving properties for relativistic pseudopotential used in the LDA (local-density approximation)[2] context.
Laboratoire de Physique de la Matière
Condensée (LPMC), Département de Physique,
Faculté des Sciences,
Université Ibn Tofail, BP 133-14000
Kénitra, Morocco.
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Volume 5, Part 1 article 9
Bifurcations sets
of the Sretensky
axial symmetric gyrostat
S.DEKKAKI, A. LASSAS, A.OUAZZANI-T-H and M.OUAZZANI-JAMIL
In this paper, we perform an adapted Deprit coordinate transformation and we analyse the flow evolution on the phase space for the axial symmetric gyrostat in the Sretensky case .We give a complete description of thegeneric bifurcations of the common level sets of the first integrals. A numerical investigation of these bifurcations is considered.
PACS numbers : 0240, 0230I, 0510G, 4520J.
Laboratoire de Physique du Solide ,
Faculté des Sciences -Dhar Mehraz, B.P
1796 Atlas Fès 30000 – Morocco
Email: ouazzanijamil@hotmail.com
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Volume 5, Part 1 article 10
Preparation and
magnetic interactions
in Cd1-x
Znx
Cr2
Se4
spinel
E. Loudghiri1 , M. Nogues2 , M. Taibi3 and A. Belayachi1,*
Cd1-x Znx Cr2 Se4 is a compound with spinel structure where two important frustration effects are present. The disorder in distribution of exchange interactions is due to the substitution between zinc and cadmium on tetrahedral sites. The samples in powder form were performed by the classical ceramic method. For the crystal growth, different methods were used depending on Zn and Cd concentrations. The composition was determined by X-ray measurements of the lattice constant. The direct current susceptibility measurements show that for the whole concentration range the system obey to Curie-Weiss law at high temperature. The DC magnetization, AC susceptibility and thermoremanent magnetization measurements revealed the existence of a spin-glass-like state and reentrant spin-glass behavior at low temperatures, in the middle concentration range.
1-
Laboratoire de Physique des Matériaux,
Faculté des Sciences Université Mohammed
V, B.P. 1014 Rabat,
Morocco.
2- Laboratoire de Magnétisme et d’Optique
de l’Université de Versailles (URA 1531),
Bâtiment Fermat,
45 Avenue des Etats Unis, 78035 Versailles Cedex, France.
3- Laboratoire de Physico-chimie des
Matériaux associé à l’AUF (LAF 502), Ecole
Normale Supérieure Takadoum
B.P. 5118 Rabat
Morocco.
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Volume 5, Part 1 article 11
RANDOM MAGNETIC
FIELD EFFECTS ON
ELECTRONIC PROPERTIES IN SUBSTITUTIONALLY
AND TOPOLOGICALLY DISORDERED ALLOYS
A. HOUARI, N. BENACHOUR and A.F.R. DIB
We numerically investigate the effects of the random static magnetic field on a variety of electronic properties
(localization of electron wavefunctions, spectral correlations and electrical conductance) in substitutionally and topologically disordered alloys. For this, we generate two-dimensional substitutionally disordered alloys and simulate three-dimensional amorphous structures by a molecular dynamics algorithm. As Hamiltonian models, we use the usual Anderson tight-binding model for the substitutional disorder and a tight-binding model with a set of explicit s-type orbitals for the topological disorder.We particularly focus on the effect of the random magnetic field on the localization of electron wavefunctions. In the presence of the substitutional disorder, we establish that the random magnetic field tends to delocalize the electron wavefunctions at the band center less than does the uniform magnetic field and it enhances the localization at the band edges. But, in the presence of the topological disorder, we observe the opposite effect. We show that the random magnetic field tends to delocalize the electron wavefunctions more than does the uniform magnetic field. In this respect, we demonstrate that the effect of the random magnetic field on the electron wavefunctions depends on the nature of the disorder.
PACS : 71.15.Pd, 71.55.Jv, 72.10.-d, 72.15.-v, 72.15.Rn.
Faculté des Sciences, Département de Physique, Université de Tlemcen, 13000. ALGERIA
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Volume 5, Part 1 article 12
Random anisotropy
studies in
amorphous Fe80-x+x'
Hox
B20-x'
alloys (0<x<16; 0<x'<4)
A. Kaala , O. El Marrakechia , H. Lassrib and S. Sayouria
In this paper, we have carried out a systematic study of the exchange and anisotropy effects on magnetic behavior of amorphous Fe80-x+x' Hox B20-x' (0<x<17; 0<x'<4) alloys. Primary analysis of magnetization data have led to the conclusion that the holmium magnetic structure is collinear. Exchange parameters, governing the magnetic ordering of our alloys, have been calculated from both mean field theory and high-field magnetization analyses. Study of the magnetization using the Chudnovsky's real space model has allowed us to determine the overall anisotropy constant, KL, from which we have determined, separately, the anisotropy energies for the iron and the holmium sublattices. Comparison of these two parameters to the exchange energies shows that the anisotropy to exchange ratio is small in these alloys.
a
Laboratoire de Physique Théorique et
Appliquée, faculté des sciences Dhar
Mahraz,B.P.1796, Fès-Atlas,
Morocco
b Laboratoire de Physique des Matériaux et
de Microélectronique, faculté des sciences
Ain Chock, Route d’ElJadida, km-8, Ain
Chock, Casablanca,
Morocco.
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Volume 5, Part 1 article 13
Magnetic elementary
excitations effects
on a Co super-lattice properties
A. Fahmi and A. Qachaou
The magnetization and the spin wave spectra are studied for a cobalt super-lattice, using the localized spins Heisenberg hamiltonian with nearest neighbors and next nearest neighbors exchange interactions. The added magnetic dipolar and anisotropy effects are discussed also.The calculation of the spin waves dispersion curves and the magnetization are carried out in the framework of Green’s functions. As experimentally expected, our results show that the surface magnetization is smaller than the inner one.
Keywords: Spin waves, super-lattices, Green’s functions, dispersions curves, magnetization.
Laboratoire de Physique de la matière condensée, Faculté des sciences, Kenitra, Morocco.
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Volume 5, Part 1 article 14
ONE STEP
ELECTRODEPOSITION
OF CuInSe2
THIN FILMS
F. Chraibi1,2 , M. Fahoume2, A. Ennaoui2,3 and J. L. Delplancke1
Formation of CuInSe2 (CIS) thin films from aqueous solution containing citrate as complexing agent is reported. The surface morphology and the composition of the deposited films are characterized by scanning electron microscopy (SEM). The texture of the deposits and their compositions are analyzed by X-ray diffraction and transmission electron microscopy (TEM). Annealing of the films at 350°C in flowing argon electrodeposited at potentials in the range [-0.24, -0.4 (V vs Ag/AgCl)] resulted in the formation of alpha-Cu 2 Se (JCPDS 24-1131) and CuSe (JCPDS 6-0427). On the contrary, annealing in the same conditions of the films electrodeposited between -0.4 and -0.6 V vs Ag/AgCl led to the formation of chalcopyrite CuInSe 2 (JCPDS 23-209) with alpha-Cu 2 Se (JCPDS 24-1131) as secondary phase. The formation of CuInSe 2 films with a chalcopyrite structure and good stoichiometry is observed.
1
Service de Sciences des Matériaux et
Electrochimie, Faculté des Sciences
Appliquées, Université Libre de Bruxelles,
CP 194/ 03, Avenue F.D. Roosevelt 50 B-1050 Bruxelles,
Belgium.
2 Laboratoire de Physique des Matériaux,
Département de Physique, Faculté des
Sciences, Université
Mohammed V, 1 Avenue Ibn Batouta, BP 1014, Rabat, Morocco.
3 L.P.M.C., Faculté des Sciences,
Université Ibn Tofail, BP 133-14000,
Kénitra, Morocco.
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Volume 5, Part 1 article 15
Study of
adatoms diffusion through
current density fluctuation functions
K. Saadounia , A. Hadera , Y. Boughaleba , R. Nassifa,b and A. Ayadic
In this work, we investigate the diffusion process by using a mean field lattice gas dynamical model. The temporal correlation function of the current density is calculated in a probe area of radius R. The latter is considered to test if the developed formulation can be applied to reproduce STM experiments. The obtained results concerning the effective diffusion coefficient exhibit clearly the order disorder transition effect translated by two minima appearing respectively at p=1/3 and p=2/3. The effect of the ordering phase at p=1/3 requires a threshold size more precisely, the minimum size system where, the ordering phase effect begins, to appear here is R=5.
PACS : 66.30.D;64.60;61.16.Ch ; 68.37Ef
a
Laboratoire de Physique de la Matière
Condensée, Université Hassan II-
Mohammadia Faculté des Sciences Ben M’sik
Casablanca- Morocco
b Laboratoire de Physique de la Matière
Condensée, Université Chouaib Doukkali
Faculté des Sciences El Jadida- Morocco
c Ecole nationale des Sciences appliquées
Université Cadi Ayyad Marrakech- Morocco
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Volume 5, Part 1 article 16
Growth of homopolymer chain
A.Benyoussef1 , Y.El Amraoui2 and A.El kenz1
Thermodynamic and kinetic properties of an homopolymer chain, in two dimensional square lattice, are studied by the use of chain growth algorithm based on the self avoiding walks process. Which is in accord with what happen in nature. All monomers are considered to be hydrophobic. In the thermodynamical study we examine the critical behaviour of the chain by following the evolution of the chain geometry with temperature. This is done by studying the behaviour of the mean distance R chosen to describe the homopolymer structure. Moreover, we give the behaviour of thermodynamic quantities such as conformational energy and specific heat. The effect of a force applied, in a fixed direction, on the chain when it is growing is also investigated. Finally, in a kinetic study, we analyse the evolution with temperature of the mean time necessarily for a given conformation to reach its native state.
(1)
Laboratoire de Magnétisme et de Physique
des Hautes Energies, Département de
Physique, Faculté des Sciences, B.P. 1014,
Rabat,Morocco
(2) Faculté des Sciences et Techniques,
Errachidia, Morocco.
Copyright © The Moroccan Statistical Physical Society. [mjcm@fsr.ac.ma]. Last modification : December 2009.
ISSN : 1114-2073