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Volume 8, article 1

 

Elaboration and characterization of Co-Zn2 SiO4 pigments

H. Ahamdane1, M.A. El Idrissi Raghni 1, F. Bensamka1 and A. Outzourhit2

In this communication, we reports results on the synthesis of Zn2-xCoxSiO4 (0≤x≤1) ceramic pigments by sol-gel method with the main aim of achieving high purity at lower temperatures. The second objective is to obtain a variety of colours (turquoise, purple, violet and blue) with a minimum quantity as possible as of cobalt. The materials were investigated by X-ray diffraction, infra-red spectroscopy, UV-visible spectroscopy, Lab-colour measurements and Scanning Electron Microscopy (SEM).

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Keywords : Amorphous carbon, Tungsten oxide, Interface, Reflectometry, X-ray diffraction, EDAX, RF sputtering

1 Laboratoire des Sciences des Matériaux, Faculté des Sciences Semlalia, Marrakech., Morocco.
2 Laboratoire de physique du solide et des couches minces, Faculté des Sciences Semlalia, Marrakech, Morocco.

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Volume 8, article 2

Size And Chirality Effects On Raman Spectrum
Of Double-Wall Carbon Nanotube Bundle

K. Sbai1, A. Rahmani1, H. Chadli1 and J. L. Sauvajol2

We study the tube size and bundling effects on Raman active breathing-like phonon modes (BLM) and tangential-like phonon mode (TLM) of double-walled carbon nanotubes (DWCNT) in the framework of the bond polarization theory, and use the spectral moment’s method. The Raman active modes are calculated for different diameter and chirality of the inner and outer DWCNT tubes. The dependence of the Raman spectrum of bundles of identical DWCNTs as a function of the size of the bundle is analysed and additional breathing-like modes are predicted in DWCNT bundle of finite size.

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Keywords : carbon Nanotube, Raman spectroscopy, spectral moment method, simulation.

(1) Equipe de Physique Informatique et Modélisation des Systèmes, Université MY Ismaïl, Faculté des Science, BP 11201, 50000 Meknès, Morocco.
(2) Laboratoire des Colloides, Verres et Nanomatériaux (UMR CNRS 5587) , CP026, Université Montpellier II, 34095 Montpellier Cedex 5, France.
Corresponding Author : email abdelali@fs-umi.ac.ma.

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Volume 8, article 3

Study Of Inertia And Stoichiometric Effect On Surface Diffusion By Monte Carlo Method

M. Noureddine1,*, B. Kaoui1, R. Nassif1,2, Y. Boughaleb1

In this work, we investigate the inertia and stoichiometric effect on surface diffusion of adsorbates particles. The study is done by means of Monte-Carlo simulation in the framework of the lattice gas model. Only first neighboring repulsive pair interaction is considered. We concentrate on the behaviour of the tracer diffusion coefficient Dt(θ), as a function of surface coverage θ in the case where two type of particles A and B are adsorbed. A and B are only different by their mass. The results shows that θt ordering phenomenon is not strongly influenced. However the diffusion process is decreased by inclusion of heavy particles.w.

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1 Laboratoire de physique de la matière condensée, Faculté des Sciences Ben M'sick, Casablanca / Morocco.
2 Laboratoire de physique de la matière condensée, Faculté des Sciences El Jadida / Morocco.

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Volume 8, article 4

Nonperturbative Analysis of the Harmonic Oscillator with a Time-Dependent Frequency

A. Fedoul*, A.L .Marrakchi, S. Sayouri* and A. Chatwiti

We apply the Floquet theorem and the resonating averages method to solve the Schrödinger equation of the harmonic oscillator whose frequency varies periodically with time. We determine its Floquet states and its corresponding wave functions. The formalism provides an efficiency tool for analyzing the various transition probabilities as well as the uncertainty relation of the system. The effect of a periodic external force on the Floquet states and the two-photon algebra realization are shortly discussed.

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PACS.  number(s): 03.65.Ge; 03.65.Fd; 42.50.p.

Keywords: Floquet theorem; quantum oscillator; resonating averages.

LPTA, Département de Physique, Faculté des Sciences Dhar Mahraz BP. 1796, Fes-Atlas, Morocco
*Corresponding authors. E-mail : azfe1@ caramail.com or ssayouri@ yahoo.com

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Volume 8, article 5

Modeling of conduction properties of Schottky diodes in Polymer

A. Aziz1,2, Y. Khlifi1, K. Kassmi1,*, F. Olivié2

This work deals with the modeling of experimental current-voltage (I-V) characteristics according to the temperature of P type Schottky diode in polymers. The results obtained show that conduction in the fabricated structures depends on temperature and bias the mode (forward or reverse).
Under reverse bias, current increases significantly with temperature. This is due to the thermoionic conduction, affected by the lowering of the potential barrier at the metal /polymer interface due to the image charge effect. The analysis of current-voltage characteristics has enabled us to derive the saturation current and, also, the potential barrier at the metal/polymer interface according to temperature. It has been shown that the value of this barrier without image charge effect, is in the order of 0. 3eV.
Under forward bias, current increases with temperature. It is of the thermoionic type at low voltage (-0.4 Volt<V< 0 Volt). It has been shown that the values of the ideality factor depend very little on temperature: varying from 1.5 to 4. However, saturation current increases with temperature: when temperature increases by approximately 6%, current increases by 20%. The values of saturation current for temperatures in excess of 200°K are confirmed by the values found in reverse bias. For temperatures less than 200°K, saturation currents in reverse mode are important relative to that obtained in forward mode. This is attributed to the electrical properties of polymer at low temperatures in reverse mode.
At high voltages (V<-0.4 Volt), the current is attributed to the resistance effect of polymer. This resistance is evidenced by the high current and drops with temperature. Its analysis has allowed us to derive the mobility of the carrier charges: when temperature varies from 105°K to 425°K, mobility varies from 3 10-5(cm2V-1S-1) to 7 10-5(cm2V-1S-1).

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1 Université Mohamed Premier, Faculté des Sciences, Dépt de Physique, (L.E.A.A), Route Sidi Maafa BP 524, Oujda, Morocco.
             2 Laboratoire d’Analyse et d’Architecture des Systèmes (LAAS-CNRS), 7 Avenue du colonel Roche, Toulouse 31077, France.
            * E. mail : khkassmi@yahoo.fr

This work has been supported by :
            • The « comité Franco-Marocain ‘Action Intégrée’, N° MA/03/78, »
            • The « Programme Thématique d’Appui à la Recherche Scientifique (PROTARS III), N° D43/06. »

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Volume 8, article 6

Magnetic properties of mixed spin Ising system with modified surface-bulk coupling:
Monte Carlo treatment

N. Benayad* and , T. Lahcini and A. Fathi

A Monte Carlo simulation is used to study the three dimensional mixed spin-½ and spin-1 Ising model with intrasurface JS and surface-bulk J^ interactions modified with respect to the bulk exchange interaction JB. In this investigation, the new parameter J^ strongly affects the phase diagram obtained in the case J^ = JB. We have found three types of phase diagrams which show some qualitatively interesting features, i.e. variety of phase transitions and multicritical points. One of the most qualitatively interesting features of the surface is the existence of two possible ferrimag-netic orderings, when the ratio R1 = J^/JB belongs to an appropriate range. A compensation point in the surface magnetization is found when the ratio of the surface and bulk exchange interactions belong to certain ranges. This phenomenon may have important applications in technology such as thermodynamic writing and erasing at the compensation point. Comparison between Monte Carlo results and those obtained by mean field theory is also made.

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PACS.  75.10.Hk ; 75.40.Cx ; 05.45.-a ; 05.70.-a

Keywords: xed spin; Surface magnetism; Monte Carlo simulation; Phase diagrams; Magnetizations; Compensation points.

Groupe de Mécanique Statistique, Laboratoire de Physique Théorique, Faculté des Sciences Aïn Chock, B.P. 5366, Maârif, Casablanca, Morocco.


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Volume 8, article 7

Study of the magnetic order in chromium

spinel systems

M. Hamedouna,*, K. Bouslykhanea, R. Masrour a, F. Talbia, A. Hourmatallaha, b and N. Benzakour a

We present a study of the magnetic properties of the A1-x CuxCr2X4 (A=Dp,Zn,....; X=S,Se,O,...)chromium spinel systems. Using the mean field theory, we have evaluated the nearest neighbour, the next-neighbour super-exchange, and the third next nearest neighbour interaction J1(x), J2(x) and J3(x), respectively for the Zn1-xCuxCr2Se4and J1(x), J2(x) for the Cd1-xCuxCr2Se4systems in the whole range of concentration 0≤x≤1.

By using the high-temperature series expansions combined with the Padé approximants method, we have obtained the magnetic phase diagrams in Tc versus dilution c.

A spin glass phase is predicted for intermediate range of concentration. The obtained results are in agreement with experimental ones obtained by magnetic measurements for the systems studied. The critical exponents associated with the magnetic susceptibility g and the correlation lengths n have been deduced. The obtained values are comparable to those of 3D Heisenberg model, and are insensitive to the dilution c.

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PACS.  74.25.Ha; 71.71. Gm; 75.40.Cx; 71.10. Hf

Keywords:  Spinels, magnetic properties, exchange interactions, critical exponents, Phase diagrams.
a Laboratoire de Physique du Solide, Université Sidi Mohammed Ben Abdellah, Faculté des sciences, BP1796, Fes, Morocco.
b Equipe de Physique du Solide, Ecole Normale Supérieure, BP 5206, Bensouda, Fes, Morocco.
 Corresponding Author e­mail: hamedoun@hotmail.com

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Volume 8, article 8 

Evaluation Of The Heavy Metals Accumulate 

In Samples Of TheSediments, Soils 

And Plants By Icp­oes With The Average Sebou

Amri N1, Benslimane M1, Zaoui H1, Hamedoun M*,1, Outiti B2

The urban, industrial and artisanal wastes liquid of the town of Fez have a very remarkable impact in the valley of Sebou. For that, various samples of sediments, agricultural grounds and plants were collected upstream like downstream from the junction Oued Fez- Oued Sebou along about thirty the kilometers; and analyzed by the method of the optical spectrometry of emission to source of plasma in inductive coupling (ICP-OES). These analyses enabled us to evaluate the contents of heavy metals such as: Ba, Zn, Cr, Ni, Co, Cd, Pb, Cu and others. All the results record a high degree of contamination of the metal elements to the state of trace in samples of sediments, grounds and plants irrigated with worn water containing of the particles of suspended materials. We could establish significant correlations of each metal for the various compartments of the ecosystem.

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Keywords: heavy metals, sediment, soil, plant, Sebou River, Fez River

1 Laboratoire de Physique du Solide, Département de Physique,  Faculté des Sciences Dhar Mehraz, B.P : 1796 -Atlas.- Fès-Morocco.  Tél : +21255733349. 

E-mail: Hamedoun@hotmail.com         

2 Laboratoire de l’institut Eawag de Zurich- Suisse.

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Volume 8, article 9

Magnetic properties in amorphous

Co95­xDyxZr5 thin films

K. Roky1,2, F. Annouar3, H. Lassri3 , H. Hassini3, 
M. Ayadi3, M. Omri3 and A. El moussaoui2

Amorphous Co95-xDyxZr5 thin films were prepared by RF sputtering and their magnetic properties were studied as a function of temperature and for the composition range 0<x<30. The mean field theory has been used to explain the temperature dependence of the magnetization. The exchange interactions between Co-Co and Dy-Co atom pairs have been evaluated. The magnetic phase diagrams are presented.

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Keywords: Amorphous Co95-xDyxZr5 thin films; Mean field theory; Exchange interactions

1Département de Physique, Facuté des Sciences et Techniques de Tanger, Morocco.

2Département de Physique, Faculté des Sciences de Tetouan, Morocco.

3Laboratoire de Physique des Matériaux et de Micro-électronique, Faculté des Sciences Aïn Chok, Université Hassan II, Maarif, B.P. 5366, Casablanca, Morocco.

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Volume 8, article 10

THE IRON SPIN TEXTURE IN ANNEALED
AMORPHOUS Fe/Tb MULTI-LAYERS

M. Sajieddine1, M. Sahlaoui1, E. Agouriane1,
H. Lasri2, Ph. Bauer3 and J. Ghanbaja4

Fe/Tb multilayers have been obtained by vacuum evaporation with Tb-layer thickness fixed to 40Å and amorphous Fe-layer thickness fixed to 19Å. 57Fe-Mössbauer spectrometry was used to obtain information on the structure and the spin texture of the multilayers before and after annealing at 530K for different durations of the annealing. The Mössbauer results indicate that the Perpendicular Magnetic Anisotropy (PMA) was stabilised and reinforced after annealing.

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Keywords: magnetic multilayers, magnetic anisotropy, Mössbauer spectrometry.

1LPM, Université Cadi Ayyad, F.S.T., BP 523, 23000 Béni-Mellal, Morocco.

2 LPMM, Faculté des Sciences, Aïn Chock, Casablanca, Morocco.

3 LSGS, Ecole Nationale des Mines, Parc de Saurupt, F-54514 Nancy France

4 LCMS, UHP, Nancy-I, BP 239, F-54042 Nancy France

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Volume 8, article 11

 

Characterization of Hydrogen Plasma used for Introducing Hydrogen into Semiconductors

O. Meglali, M. S. Aida, N. Attaf

This paper reports the investigation result of RF power effects on the RF hydrogen plasma parameters. The hydrogen plasma parameters are measured experimentally in the center of the deposition chamber by means of the cylindrical Langmuir probe. The measurements are done at 0.2 mbar hydrogen gas pressures. The applied discharge powers are between 50 W and 200 W. It is found that the electron and ion densities increase with the RF power. The ion density dependence of the cathode sheath voltage is fitted to Ni(cm-3)=-3.5 1010 + 9.2  107 (Vo - Vdc). The plasma and floating potentials are less sensitive to RF power.

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Keywords: Hydrogen plasma, RF power, Langmuir probe, Pressure.

Laboratoire des couches minces et interface, unité de recherche physique des matériaux et applications, Université Mentouri -Constantine.Algérie

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Volume 8, article 12

 

Critical behaviours of a ferrimagnetic alternating superlattice with disordered interfaces.

Y. Belmamouna and M. Kerouada,*

The phase diagrams and magnetic properties of a ferrimagnetic multilayer system consisting periodically of L layers of spin-1/2 A atoms, L layers of spin-1 B atoms, and a disordered interface in between that is characterized by a random arrangement of A and B atoms of ApB1-p type and a negative A-B coupling, are investigated by the use of an effective field method within the framework of a single cluster theory. The effects of the disorder in the interface, the bulk and interface anisotropies and different coupling constants on the magnetic properties are examined in details. A number of characteristic features such as the possibility of a compensation point are found.

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a LPMMS, Département de Physique, Université  Moulay Ismail, Faculté des Sciences, BP 4010, Beni M’Hamed, Meknès, Morocco.

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Volume 8, article 13

PZT thin films preparation
by pyrosol process

A. El Bouchikhia, E. Philippotb, M. Et-tabiroua

Lead Zirconate titanate [Pb(Zr,Ti)O3] thin films were deposited on Si (111) substrates by pyrosol process based on the pyrolysis on a heated substrate of an aerosol produced by the ultrasonic spraying of a solution. The films were characterized by X-ray diffraction to control the morphology and the preferential orientation of the thin film.

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a Laboratoire de Physico-Chimie du Solide (LPCS), Université Ibn Tofail, Faculté des Sciences BP 133, 14000 Kénitra, Maroc

b Laboratoire de Physicochimie de la Matière Condensée, UMR 5617 CNRS,  CC03, Université de Montpellier II, Sciences et Techniques du Languedoc, F34095 Montpellier cedex 5, France

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Volume 8, article 14

Mean field study of decorated
ferrimagnetic Ising model

A.Benyoussef, A. El kenz and M. El yadari

 The magnetic properties of a decorated ferrimagnetic Ising model consisting of two magnetic atoms A and B with spins σA= 1/2 and SB=1 are investigated by the use of the mean field approximation. Transition temperatures and the existence of the one or double compensation temperatures of the decorated ferrimagnetic square lattice are examined.

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Keywords: Decorated Ising model; ferrimagnetism; compensation temperature.

Laboratoire de Magnétisme et de physique des Hautes Energies Département de physique, B.P 1014, Faculté des sciences, Rabat, Morocco.

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Volume 8, article 15

Self Consistent RPA applied to the extended

Hubbard Model

S.Harir1,   M.Bennai1, Y.Boughaleb1,2, M.Fliyou3

Using the extended Hubbard model with the Self Consistent Random Phase Approximation (SCRPA), we study the intersite interaction effect on the dynamics of N electrons. We consider the extended Hubbard model containing intrasite and intersite interactions, and we apply this model to a system of  two interacting atoms, where each atom presents one free electron. The resolution of this tow sites problem is done by the SCRPA approximation; our calculations allow as studying the intersite interaction effect on the excitation energies of system. We have showed that the attractive interaction between the electrons of the neighbour’s atoms is the origin of supplementary conductivity of the system.

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PACS.  71.10,-W.75.10.Jm,72.15.Nj

Keywords: SCRPA, extended Hubbard, ph-RPA

1. Laboratoire de Physiques de la Matière Condensée, Faculté des Sciences Ben M’.Sik, Université Hassan II-Mohammedia Casablanca, Maroc.

2. LPMC, Faculté des Sciences d’.Eljadida, Université Chouaib Doukkali, Maroc.
3. LPS, ENS, Marrakech, Maroc

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Volume 8, article 16

Dielectric characterization
of hydrothermally PREPARED
(Cu,Sb)-doped BaTi1-xZrxO3

A. Outzourhit, M.A. El Idrissi Raghni, M. L. Hafid, F. Bensamka

Powders of copper-doped BaTi1-xZrxO3 have been synthesized using the hydrothermal process. The starting materials were powders of  BaO and TiO2, ZrO2.xH2O gel, and an aqueous solution of Cu2+ / Sb5+. The obtained powders were cold compacted and sintered at 1280°C. Impedance spectroscopy measurements have been performed on these ceramics and the results were analyzed using the empiric Cole-Cole model. A procedure to evaluate the electric properties of the grain boundary and bulk grain has been developed based on electric polarization model of double layered dielectrics.

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Laboratoire des Sciences des Matériaux.Faculté des Sciences Semlalia, Université Cadi Ayyad, Marrakech, Morocco.

 

Copyright © The Moroccan Statistical Physical Society. [mjcm@fsr.ac.ma]. Last modification : December 2009.

ISSN : 1114-2073