Volume 7, article 1
Dj. Benyahia, B. Bouhafs, and F. Lassouani
Light reflected from a dielectric- metal interface describe the existence of resonant modes of the collective oscillation in electron density. The experimental configuration proposed by Otto and Kretschmann- Raether can be used to characterizes the optical properties of thin metallic films in contact with a dielectric medium. In far-field detection, the angular dependence of the reflectivity on Ag/ ambient air shows a sharp minimum beyond attenuated total reflection. At a wavelength, λ the geometric parameters influence strongly the angular resonance θSP. In the case of Ag, λ = 633.0 nm, at the optimal thickness, d = 50.8nm, a resonant coupling is reaches between incident photons and free electrons in the angular range 45° < θSP < 46°. The angular resonance is associated with the optical phenomenon of an energetic transfer predicted theoretically.
Keywords : Evanescent wave, Resonant modes, Far-field Detection, Diagnostic of the metal/dielectric Interface.
Université Abou Bekr Belkaid, Faculté des Sciences, Laboratoire de Physique Théorique, BP 119, Tlemcen 13000. Algérie
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Volume 7, article 2
Electrical
characterization
of the junctions P+ N by C-V technique
H. Bouchenafa, S.Rachedi, D. Ghaffour, S. Kerai and K Ghaffour*
Technique CV exploits measurement in mode of small signals for a relatively high frequency of the capacity of a junction metal-semi driver or a junction P+ NR (or PN+ polarized in reverse by a tension V R The experimental analysis of this technique makes it possible to determine some electric properties of the junctions P+ N or Schottky.
We describe here, the method used and we expose then the results obtained by this technique on diodes containing silicon (Si).
Keywords : Junction P+ N, Schottky, Capacity-tension
Unit of Research Materials and Energies
Renewable BP.119 – 13000-Tlemcen-ALGERIE
Tel: +213 (43) 21 58 90, Fax: +213 (43) 21 58 89
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Volume 7, article 3
Study of composed of insertion graphite hydride of sodium by electronic paramagnetic resonance (EPR)
N. El Alem, M. Ez-Zahery
From the electronic point of view, graphite is a semi metal, the density of the charge carriers is approximately 10-4 by carbon atom. Insertion in the graphite of made up donors of electrons, is accompanied by a strong increase in conductivity in the plan and along the axis c. Reaction of the sodium hydride with the graphite led to the formation of ternary hydrogenated compounds of different stages. The electronic paramagnetic resonance applied to these compounds indicates the conducting character of these species.
Keywords: graphite, hydride of sodium, composed of insertion, electronic, standard paramagnetic resonance dysonien, width with middle height.
Mineral Chemistry laboratory Applied and Genius of the Processes, Faculty of Science quoted ADAKHLA B.P 8106 Agadir.
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Volume 7, article 4
Inversion of the excitonic spectrum in semiconductor microcavities
A.V. Kavokina, G. Malpuechb
We show that coupling of odd photonic modes in microcavities with odd excitied exciton states in wide quantum wells (WQWs) situated at the nodes of the electric field of the cavity mode may lead to the inversion of the excitonic spectrum: an odd exciton-polariton state (X2) may lie at lower energy than even (X1) exciton state. The kinetics of exciton-polariton relaxation is expected to be very peculiar in this case: the excitons are accumulated in the optically inactive even state at the beginning, and then scatter to the upper and lower odd polariton modes. This regime is favourable for Bose-Einstein condensation of X1 excitons whose life-time becomes much longer because of their decoupling from the cavity mode. Experimentally, the evidence for condensation of “dark” X1 excitons would come from the coherent emission of light from the ground odd exciton-polariton state. If the WQW is shifted from the node of the field, X1 exctions get coupled to light, and the anticrossing between even and odd polaritons can be distinguished in reflection spectra.
PACS. 42.55.Sa; 71.36 +c; 78.47+p; S7.12
a Physics and Astronomy School, Univeristy
of Southampton, SO17 1BJ Southampton, United Kingdom.
b LASMEA, UMR 6602 CNRS, Université
Blaise-Pascal, 24, av des Landais, 63177, Aubière, France.
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Volume 7, article 5
Cr-based MOCVD layers as conducting diffusion barriers for copper metallization
F. Maury, F.D. Duminica, C. Gasqueres
Two types of amorphous Cr-based thin films, CrCxNy and CrSixCy, were grown by low pressure MOCVD on Si substrates using respectively Cr(NEt2)4 and Cr[CH2SiMe3]4 as single-source precursor in the low temperature range 400-420 °C and 475-500 °C. Their properties as conducting diffusion barrier against Cu were investigated and the results are discussed. CrSixCy exhibits a better thermal stability and a good Cu wettability but a high resistivity, which is detrimental for this application. CrCxNy has a low resistivity, a satisfactory stability up to 650 °C without undesirable interfacial reactions and an excellent conformality.
Keywords: : MOCVD; CrCxNy films; CrSixCy films; Diffusion barriers; Cu metallization;
Centre Interuniversitaire de Recherche et d'Ingénierie des Matériaux, ENSIACET, 118 route de Narbonne, 31077 Toulouse cedex 4, France.
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Volume 7, article 6
Optimization of thin film growth: Materials for energy storage and conversion
A. Rougier, Y. Makirnura, N. Penin, X. Darok and J.-M. Tarascon
Through three examples taken in the field of energy storage and conversion, this paper reports how the property of thin films can be optimized by tuning the growth conditions. Focusing on the influence of the film composition, the substrate temperature and the pressure, oxides, fluorides, metal and hydrides thin films were successfully grown using the Pulsed Laser Deposition technique. A careful screening among a large range of metal addition (M=Co, Ta, W<20 %) enables the determination of the Ta and W compositions leading to the highest cycling stability of electrochromic Ni-based oxide thin films cycled in KOH electrolyte. The optical properties of Mg thin films are strongly sensitive to the chamber pressure as shiny metallic and transparent films are deposited in vacuum and under an Ar/H2 mixture, respectively. Optical changes were also achieved by ex situ hydrogenation of Mg-Cx films. Finally, the benefit of enlarging substrate temperatures to negative values is illustrated through the example of FeFx thin films, for which the substrate temperature is a key factor governing the FeF2 or/and FeF3 phase deposition.
Keywords: Pulsed Laser Deposition, Thin films, Growth Conditions
Laboratoire de Réactivité et de Chimie des Solides, CNRS UMR-600 7, Université de Picardie Jules Verne, 80039 Amiens Cedex, France.
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Volume 7, article 7
Crystallographic and dielectric properties of the LiZnAs(1-x)PxO4 solid solution
M. Azroura, L. Biha, L. El Ammarib, D. Mezzaneb, A. Alimoussac, B Elouadid
Crystallographic and dielectric studies of the system LiZnAsO4–LiZnPO4 have been investigated. Solubility limits of phosphorous into LiZnAsO4 was found. A new solid solution LiZnAs(1-x)PxO4 with 0 ≤ x ≤ 0.5 is then evidenced. IR spectra show the presence of XO4 groups in the network of these materials. Correlations between structure and dielectric properties are established.
a UFR-PCMI : Céramiques et Verres, Faculté des Sciences et Techniques Errachidia, Morocco
b Laboratoire de Chimie du Solide Appliquée, Faculté des Sciences, Rabat, Morocco
c Département de physique, Faculté des Sciences et Techniques-Guéliz Marrakech
d LEACIM, Université de La Rochelle, France
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Volume 7, article 8
The effect of the surface field on the phase diagrams of a transverse Ising thin film
H. Arhchoui and Y. El Amraoui
Within an effective field theory (EFT), the phase diagrams of a transverse Ising thin film (TIM) has been investigated. The effects of the Ωs on the critical temperature are discussed by including the modification of surface exchange interaction. The phase diagrams are also determinated as function of the transverse field for different values of the film thickness n and for same value of ∆s
Laboratoire de Physique Statistique et Modélisation de systèmes, département de Physique B.P. 509, Boutalamine, Errachidia, Morocco.
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Volume 7, article 9
Characterisation of the porous silicon layers
Z. Fekih, F. Z. Otmani, N. Ghellai, N. E. Chabanne-Sari
Porous silicon (PS) is obtained by anodic attack of single-crystal silicon in concentrated hydrofluoric acid solution. All the properties of the porous silicon layer, such as porosity, the thickness and the diameter of the pores depend in a critical way of the anodization parameters.
This present work aims to study the evolution of the porous silicon various properties according to the anodization parameters. Also we are interested in the various experimental aspects intervening in manufacture and the characterization of the thin layers of porous silicon by gravimetry and ellipsometry.
Keywords: Porous silicon, anodization, ellipsometry, porosity.
Unit
of research of Materials and renewable
Energies (U.R.M.E.R) University Abou -
Baker Belkaid B.p: 119 TLEMCEN 13000
ALGERIA
Tel/Fax: 043. 21. 58. 90 & 89
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Volume 7, article 10
Symbolization of the
electric diagram
of the marketed solar panels
in the Orcad- Pspice environment
A. Aziza, K. Kassmia, F. Oliviéb, A. Martinezb
In this paper, focuses on how to create a special library of some marketed solar panels in the Orcad-Pspice environment using the design features provided by the founder, we established and implanted in Orcad-Pspice the electric scheme of the solar panels according to their architecture. This makes it possible to model the operation of each panel when it is closed on a resistive load. Also, simulation is used to determine the electric characteristics of these panels according to temperature and solar irradiation.
a Université Mohamed Premier, Faculté des Sciences, dépt de Physique, LEAA , Oujda, Morocco.
b Laboratoire d’Analyse et d’Architecture des Systèmes (LAAS/CNRS), 7 avenue du Colonel Roche, 31 077, Toulouse, France.
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Volume 7, article 11
Algorithm for
extracting infinite clusters
support of mechanical and electrical
properties
in percolation networks
N. Serir and A. Sari
The concept of the percolation is a rather intuitive simple model for the physical problems of very different nature which appear in strongly inhomogeneous mediums. Being a phenomenon in threshold, it represents an some interest practises in many theoretical and industrial applications, so that a good comprehension of the phenomena of percolation becomes extremely useful, the interest of a reliable algorithm, economic and rapid allowing the search for percolants structures in the percolation of bonds. In our laboratory, we re-examined a method for extraction of the infinite cluster. Method based on sweeping and the treatment row by row of the structure. This will enable us to accelerate the evaluation of conductivity as well as the currents distribution of a network formed by a random distribution of electric resistances.
Keywords: percolation, percolation threshold, clusters distribution, labelling technique, random resistor networks, and infinite set of exponents.
Université de Tlemcen, Faculté des Sciences, Département de Physique, Laboratoire de Physique Théorique, B. P 119 13000 Tlemcen, Algérie
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Volume 7, article 12
Lamellar Precipitation in an Cu-4.5 at. % In Alloy
Z. Boumerzoug
The decomposition of supersaturated solid solution of numerous alloys during aging occurs throughout discontinuous cellular reaction resulting in the formation of the alternating structure α and β phases. The discontinuous precipitation is characterized by the presence of sharp reaction front which separates the initial state from the reaction product.
In this contribution, the morphology of cellular precipitation in an Cu-4.5 at. % In alloy has been investigated by optical microscopy and electron microscopy ( TEM and SEM ). The lamellar precipitates develop from the grain boundary into the grain by discontinuous reaction during aging at 673 K. The discontinuous precipitation clearly revealed by optical and scanning electron micrographs was observed to decompose into lamellar structure. It has been observed different orientations of lamellae in the same cell and the discontinuous reaction is more developed in certain sites of matrix, like grain boundaries and interphases of matrix. On the other hand, the shape of reaction front is analyzed by transmission electron microscopy.
Department of Metallurgy, Biskra
University, Biskra- 07000 – Algeria
Tel/Fax : ( 213 ) 33 732127
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Volume 7, article 13
Permanent and Dynamic Behaviours of Self-excited Induction Generator In balanced mode
M. L. Elhafyani, S. Zouggara, M. Benkaddourb, Y. Zidanic
Due to its various advantages over the synchronous generator, the induction machine (IM) can be used as a generator in remote and rural areas. It be haves as a generator when its rotor is driven above its asynchronous speed. The required reactive power is provided by a local capacitors bank connected to the stator of the IM. Both permanent and transient modes of the self excited induction generator (SEIG) are studied. In both cases (loaded and no-loaded), the evolution of the output voltage for different values of the excitation capacitor and speed is presented. We analyze also, the influence of the capacitors and speed values on start-up of the SEIG. A comparison between laboratory tests and simulation results is done, that demonstrate the effectiveness of the proposed model
Keywords: Renewable energy, Self-excited induction Generator, Variable speed, Transient analysis.
a
Université Mohammed 1er, Ecole Supérieure
de Technologie LEEP BP. 473. 60000 Oujda
Morocco
b
Université Mohammed 1er, Faculté des
Sciences, Département de physique Oujda
Morocco
c Université kadi Ayad, Faculté
des Sciences et Techniques Marrakech
Morocco
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Volume 7, article 14
Analysis of Optical and
Structural Properties
of Sol–Gel TiO2
Thin Films
R. MECHIAKH, R. BENSAHA
Titanium dioxide (TiO2) is widely used in various industries (cosmetics; painting; solar cells; used-water reprocessing; electro-chromatic systems; etc.). It exists under different crystalline forms: rutile, anatase, and brookite. We have prepared our samples using an alcoholic solution of Tetra-buthylorthotitane, hydrolysed in a water/alcohol/acid mixture. The solution thus prepared was deposited by a sol–gel method on an ITO substrate. The layers undergo a heat treatment at temperatures varying from 300 with 500°C, and various dippings. DRX analysis of our thin films of TiO2 shows that the titanium oxide starts to crystallize starts from the temperature of annealing 350°C. The structure obtained is anatase. At higher temperatures (400 and 450°C), and for a number of layers (dipping iterations) increasing from 4 to 9, we observe in addition to anatase, the formation of brookite. The intensities corresponding to the lines characteristic of anatase (101) and brookite (111) increase with temperature. This increase in the intensities of the peaks is interpreted as due to an increase in size of the grains (nanocrystals) of titanium oxide with the increase in the annealing temperature. The Raman spectra confirm the presence of titanium oxide starting from the temperature 350°C, the peaks characteristic of anatase (tetragonal) appear near bands centred around 153 and around 193cm-1. For the higher temperatures (400 and 450°C) we note also the formation of brookite which corresponds to the wavelength 650 cm-1. The calculated size of the grains varies from 11.9 to 17.1nm for anatase and from 25 to 10.2nm for brookite. The index of refraction (n), and porosity (p) are calculated starting from the measured transmission spectra, and vary between 1.63 and 2.59 for n, and from 3.5 to 68.7% for porosity
Keywords: Sol-Gel; titanium dioxide; thin films; anatase; brookite.
Ceramics Laboratory, Department of Physics, Faculty of Science, Mentouri University of Constantine, Road of Ain El-Bey (25000) Constantine Algeria
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Volume 7, article 15
Multifractal Properties of an Electrical Network in the Percolation Threshold
N. Serir, A. Sari , T. Ouahrani
We consider a square network formed of random electric resistances to the percolation threshold of bond Pc=0.5. We calculate the distribution of current on the infinite cluster with a constant current and constant tension, using a method of gradient conjugated accelerated by LU decomposition. Then we study the multifractal spectrum of the current distribution. Our numerical results are in agreement with the results in literature. The form of the distribution function is nearly Gaussian with the existence of a long tail in the weak current zone. This study leads us to the following findings: the insufficiency of the multifractality to describe all scales of currents; the distribution of strong currents is well understood and it is multifractal, meanwhile the weak currents stays imperfectly known.We also obtain a part of the spectrum which describes the very weak currents that we assign to the currents scales.
Keywords: Percolation, Multifractality, Fractality.
Université de Tlemcen, Faculté des Sciences, Département de Physique, Laboratoire de Physique Théorique, B.P 119 13000 Tlemcen, Algérie
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Volume 7, article 16
On the Linear Viscoelastic Behavior of Polyolefins in the Molten State: Influence of Long Chain Branching
S. Belmiloud, A. Bensafi, M. Benmouna
This contribution presents a survey on the influence of long chain branching on the linear viscoelastic properties. The aim of this article is to provide evidence that rheological testing is a potent tool for characterising polymers in the melts. The materials chosen are linear and slightly long- chain branched metallocene- catalysed polyethylene of narrow molecular mass distribution, as well as linear and highly long- chain branched polyethylene of broad molecular mass distribution, and other sample of the big family of polyolefin’s.
The linear viscoelastic flow properties are determined in shear creep and recovery experiments by means of a magnetic bearing torsional creep apparatus. The interest of this study consists in reviewing various experimental, theoretical and simulation results of the some viscoelastic properties. The samples with a slight degree of long- chain branching exhibit a surprisingly high zero shear-rate viscosity in comparison to linear one, whereas the highly branched polymers have a much lower viscosity compared to linear samples. Slightly branched polyethylene have got a higher steady- state compliance in comparison to linear products of similar polydispersity, whereas the highly branched polyethylene of broad molecular mass distribution exhibit a surprisingly low elasticity in comparison to linear broad molecular one. The same remarks are obtained for the other samples. The actual framework leads us to say that the number of branches is less important than the topology itself. Therefore, the position and architecture of the branches along the main polymer chain are the principal factors that control the material rheology.
Keywords: Polymers, Long chain branched, ramified, viscoelasticity, polydispersity, compliance.
Université de Tlemcen, Faculté des Sciences, Département de Physique, B.P 119 13000 Tlemcen, Algérie
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Volume 7, article 17
Elaboration and characterization by XRD and SEM of the glass-ceramics in BaTiO3 – NaPO3 system
M. Azrour1, L. Bih1, L. Abbas1, Y. El Amraoui2, H. Khemakhem3, D. Mezzane4, A. Nadiri5
There is a strong need for low cost glass-ceramic materials whose high chemical stability and dielectric properties can be engineered flexibly in bulk and fiber forms. Therefore we have manufactured transparent ferroelectric glass-ceramics consisting of barium titanate (BT) crystallites in a chain metaphosphate glass matrix. Several glass compositions, in the series (1-x) NaPO3 – x BaTiO3 have been prepared by a conventional melt quenching method. The compositions have been selected on the basis of chemical stability. X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicate the formation of small particle size of BaTiO3 in the glass network when its amount is above 4 mol%.
1
UFR-PCMI: Céramiques et Verres, Equipe
Sciences des Matériaux, FST-Errachidia,
B.P. 509 Boutalamine, Errachidia Morocco
2 LPSMS, FST-Errachidia.
3 Laboratoire de Physique Appliquée,
Faculté des Sciences de Sfax, Tunisia
4 LESEO, FST-Guéliz-Marrakech, Morocco
5 UFR-SMI, Faculté des Sciences de Meknès,
Morocco
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Volume 7, article 18
dc and ac
conductivities of
the yLi2O–(1-y)[0.35(MoO3)2–0.65(P2O5)
glasses
L. Abbas1, A. Nadiri2, Y. El Amraoui3, D. Mezzane4, H. Khemakhem5
Glass formation and properties of glasses containing Li2O and MoO3 oxides have been investigated to determine the influence of lithium oxide Li2O in phosphomolybdate glasses. Conductivity spectra have been taken on yLi2O–(1-y)[0.35(MoO3)2–0.65(P2O5)] glasses at various temperatures in the frequency range 10-2Hz – 1MHz. The frequency dependent conductivity is found to display the universal dynamic response behaviour widely observed in disordered solid electrolytes. Contrary to some ion conducting glasses, no typical conductivity scaling was observed for these glasses
Keywords: phosphate, molybdenum, glasses, electrical conductivity.
1
UFR-PCMI: Céramiques et Verres, Equipe
Sciences des Matériaux, FST-Errachidia,
B.P. 509 Boutalamine, Errachidia Morocco
2 UFR, SMI, FS– Meknès, BP 4010 Beni
M’hamed, Morocco
3 Equipe de Physique Statistique et
Modélisation des Systèmes, FST-Errachidia,
BP 509, Boutalamine, Morocco
4 LESEO, FST Guéliz – Marrakech, Morocco
5 LPA, Faculté des Sciences de Sfax,
Tunisia
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Volume 7, article 19
The lamellar Na2CoP2O7 pyrophosphate: Preparation, structural and spectroscopic studies
H. Bih, I. Saadoune, M. Mansori
Intensive scientific investigations have been devoted to phosphates. These investigations have concerned the synthesis, the structural features or the physical properties (electrical, magnetic, optic, electrochemical….). As layered materials are attractive for the electrochemical applications, we have prepared and studied Na2CoP2O7 which could be used as starting material for Li2CoP2O7 preparation by Na/Li exchange reaction. Na2CoP2O7 was prepared by coprecipitation method and the structure was refined by using the Rietveld method. Na2CoP2O7 exhibits a layered structure (S.G. P42/mnm; a.= 7.704 (3) Ǻ, c = 10.293 (5) Ǻ). Within de CoP2O7 sheets, each CoO4 tetrahedron shares corners with P2O7 rings. Sodium ions are located in a very large crystallographic site. The prepared phosphate has been characterized by IR spectroscopy which confirms the structural results
Keywords: pyrophosphate; Positive Electrode; lithium-ion Batteries; Rietveld method; IR Spectroscopy
Equipe de Chimie des Matériaux et de l’Environnement - FST Marrakech, Avenue A. Khattabi, BP 549, 40000 Marrakech, Morocco
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Volume 7, article 20
Proton conductivity in Al-stevensite pillared clays
B. Rhouta1,
M. Amjoud1,
D. Mezzane1,
A. Alimoussa1,
L. Daoudi2,
E. Ech-chamikh3,
H.Kaddami4
Fine stevensite mineral fraction (< 2 m) has been extracted from natural Moroccan ghassoulite clay. Thereafter, it has been pillared by Al13 polycations species. Physico-chemical characterization, performed using X-ray diffraction (XRD), thermal analysis (TG-TDA) and Scanning Electron Microscopy (SEM) equipped with X-ray Energy Dispersion (XED) analysis, has proved that stevensite pillaring has been successfully achieved. Electrical impedance measurements, carried out onto samples before and after pillaring operation, have shown an increase in proton conductivity for pillared with respect to pristine stevensite clay mineral.
Keywords: stevensite, clay, pillaring, proton, conductivity, [Al13]-Keggin polycation
1
Laboratoire de Matière Condensée et
Nanostructures (LMCN), Faculté des
Sciences et Techniques Guéliz, BP 549,
Marrakech, Morocco
2 Laboratoire de Géosciences et
Géoenvironnement, FST Gueliz, BP 549,
Marrakech, Morocco
3 Laboratoire de physique du solide et des
couches minces, Faculté des sciences
semlalia, BP : 2390, Marrakech, Morocco
4 Laboratoire de Chimie Bioorganique et
Macromoléculaire, Faculté des Sciences et
Techniques Guéliz, BP 549, Marrakech,
Morocco
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Volume 7, article 21
A synthesis and
characterization of lanthanum potassium
niobate oxide
with tetragonal tungsten bronze (TTB) type
structure
R. Ait Benhamou, M. Daoud, A. Zegzouti, M. Elaatmani, E. Dieguez*
The main aim of this study is to lower the reaction and sintering temperatures of K2LaNb5O15 in order to improve the quality of this material.
The K2LaNb5O15 compound has been synthetized by soft chemistry (coprecipitation) and its physico-chemical properties were studied.This method permits the synthesis of chemical purty, fine powder materials with good crystallization at low temperatures.
Keywords: Ferroelectric niobate; Soft chemistry synthesis; X-ray diffraction; Scanning electronic microscopy; Dielectric response.
Laboratory of Mineral Solid State
Chemistry, Faculty of Sciences, University
Cadi Ayyad, Bd. My Abdallah, B.P 2390
Marrakech, Morocco
* Laboratory Crystal Growth, Materials
Physics Dept., Universidad Autonoma de
Madrid, 28049 Mardrid, spain
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Volume 7, article 22
New ionic conducting ceramics of NASICON type: synthesis and characterizations
A. Essoumhi1, C. Favotto1, P. Satre1, M. Mansori2, K. Ouzaouit3, A. EL Hichou4
In this work, we present a study of two NaSICON families of general formula Na2.800M1.775Si0.900P2.100O12 with M=Zr or Hf. The synthesis was carried out using sol-gel process and the synthesized precursors were characterized using coupled DTA-TG. The obtained oxides after pyrolysis of precursors were identified by X-ray diffraction. The electric properties of the sintered oxides were carried out by impedance spectroscopy (SIC). The obtained results at this conditions highlight a good improvement of electrical conductivity (σtot around 10-4S.cm-1). This value is comparable to total electrical conductivity at 300K given in the literature.
Keywords: NaSICON, Zirconium, Hafnium, sol-gel, electrical conductivity
1
Laboratoire de Physico-chimie du Matériau
et du Milieu Marin, Faculté des Sciences
et Techniques, Université du Sud Toulon
Va, BP 20132,
83957 La GARDE Cedex, France
2 Equipe de Chimie des Matériaux et de
l’Environnement, Faculté des Sciences et
Techniques, Université Cadi Ayyad, BP.
549, Marrakech, Morocco
Corresponding author: Tél. : (212)
544433404 Fax : (212) 544433170
3 Laboratoire L2MP, Faculté des Sciences
et Techniques, Université du Sud Toulon
Var, BP 20132, 83957 La GARDE Cedex,
France.
4 Laboratoire de la Matière Condensée et
Nanostructure, Faculté des Sciences et
Techniques, Université Cadi Ayyad, BP.
549, Marrakech, Morocco
_________________________
Volume 7, article 23
Algorithm for
extracting infinite clusters support of
mechanical and electrical properties
in percolation networks
N. Serir et A. Sari
The concept of the percolation is a rather intuitive simple model for the physical problems of very different nature which appear in strongly inhomogeneous mediums. Being a phenomenon in threshold, it represents an some interest practises in many theoretical and industrial applications, so that a good comprehension of the phenomena of percolation becomes extremely useful, the interest of a reliable algorithm, economic and rapid allowing the search for percolants structures in the percolation of bonds. In our laboratory, we re-examined a method for extraction of the infinite cluster. Method based on sweeping and the treatment row by row of the structure. This will enable us to accelerate the evaluation of conductivity as well as the currents distribution of a network formed by a random distribution of electric resistances.
Keywords: percolation, percolation threshold, clusters distribution, labelling technique, random resistor networks, and infinite set of exponents.
Université de Tlemcen, Faculté des Sciences, Département de Physique, Laboratoire de Physique Théorique, B. P 119 13000 Tlemcen, Algérie
_________________________
Volume 7, article 24
Electrical
conductivity of BaCeO3
synthesized
by new sol-gel method
K.
Ouzaouit, A. Benlhachemi, H. Benyaich
1
J. P. Dallas, S. Villain, J. A. Musso, J.
R. Gavarri
2
Polycrystalline BaCeO3 was prepared using new sol-gel processing at low temperature. The sample was characterized by X- ray diffraction and transmission electronic microscopy. The refined lattice parameters were found to be equal to: a = 8.782 Å, b = 6.240 Å, c = 6.217 Å. Electrical conduction was studied in the temperature range 150 to 950°C. The apparent conductivity of compacted samples was found to increase with temperature in a non linear way, from σ =2.49 10-7 S.m-1 at T =150°C to σ = 1.55 10-3S.m-1 at T =950°C. The activation energy is not constant and was found to increase from about 0.21 eV (in the temperature range: 150°C - 450°C) to 0.94 eV (in the temperature range 450°C - 950°C).
Keywords: BaCeO3, sol–gel, electrical impedance, characterization, activation energy, protonic conduction.
1 Laboratoire PCM, Faculté des
Sciences, Université Ibn Zohr, BP. 8106,
Cité Dakhla, 80000 Agadir – Morocco
2 Laboratoire L2MP (UMR CNRS 6137),
Université du Sud-Toulon-Var, BP. 132,
83957 La Garde – France.
Copyright © The Moroccan Statistical Physical Society. [mjcm@fsr.ac.ma]. Last modification : December 2009.
ISSN : 1114-2073