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Auteur Abderaheman Bouabellou |
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Titre : Élaboration et caractérisation de couches minces à base d’oxydes. Type de document : texte imprimé Auteurs : Hacène Serrar, Auteur ; Abderaheman Bouabellou, Directeur de thèse Mention d'édition : 06/11/2019 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2019 Importance : 120 f. Format : 30 cm. Note générale : 1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : physique: Sciences des matériaux Oxyde métallique couches minces CuO TiO2 spray pyrolyse sol-gel guidage optique photocatalyse Metallic oxide thin films pyrolysis spray optical guiding photocatalysis أكسید معدني طبقات رقیقة أكسید النحاس أكسید التیتان الرش و الانحلال الحراري الترسیب سائل -
جامد التوجیه البصري التحفیز الضوئیIndex. décimale : 530 Physique Résumé : In this work, we are interested in the study of thin films based on metal oxides elaborated by two chemical methods namely the pyrolysis spray and the sol-gel dip - coating. Our study is first focused on the effect of solvent on the properties of thin CuO films. Thin CuO films were prepared by the pyrolysis spray method using two different solvents: water and methanol. The structural, microstructural, morphological and optical characterizations of CuO thin films were carried out. The crystalline structure analysis using the XRD diffraction technique shows three characteristic peaks (002), (111) and (020) of the monoclinic CuO phase. The position of the peaks are shifted to the lowest angles, indicating the effect of tensile stress in the prepared films. The micro-Raman analysis confirms the results of XRD. The SEM observation shows that the morphology of the film strongly depends on the nature of the used solvent. The optical characterization of CuO- (distilled
water) sample shows a low transmittance compared to that prepared with methanol. This behavior is attributed to the simultaneous effects of thickness and solvent. Then, our study has been focused on the effect of experimental parameters and the addition of metal oxides (ZnO and NiO) on the properties of TiO2 thin films prepared by the sol-gel method. The structural characterization by means of micro-Raman spectroscopy shows vibration modes corresponding to the anatase phase of TiO2. Thin TiO2films and its compounds are characterized by micro-Raman, SEM, m-lines and Uvvisible techniques. Micro-Raman analysis shows that the TiO2 thin films are characterized by the modes of vibration of the Anatase phase. ZnO and NiO cause the decay of TiO2 vibration modes. The SEM observation shows that the addition of ZnO pushes the crystalline degradation (amorphization) of the TiO2 anatase phase. While UV.Vis analysis shows an increase in the optical gap due to the effect of amorphization and Burstein-Moss. The waveguide measurements reveal simple guided modes in both polarizations (TE0 and TM0) in all samples from which the refractive index and the thickness are calculated. A decreasing refractive index profile was observed when ZnO and NiO are introduced into thin films of pure TiO2. The photocatalytic activity is evaluated by the degradation of MB. The obtained results show that the thin films of pure TiO2 are the best
photocatalytic materials.
Note de contenu : Liste des publications.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/SER7582.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11419 Élaboration et caractérisation de couches minces à base d’oxydes. [texte imprimé] / Hacène Serrar, Auteur ; Abderaheman Bouabellou, Directeur de thèse . - 06/11/2019 . - جامعة الإخوة منتوري قسنطينة, 2019 . - 120 f. ; 30 cm.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : physique: Sciences des matériaux Oxyde métallique couches minces CuO TiO2 spray pyrolyse sol-gel guidage optique photocatalyse Metallic oxide thin films pyrolysis spray optical guiding photocatalysis أكسید معدني طبقات رقیقة أكسید النحاس أكسید التیتان الرش و الانحلال الحراري الترسیب سائل -
جامد التوجیه البصري التحفیز الضوئیIndex. décimale : 530 Physique Résumé : In this work, we are interested in the study of thin films based on metal oxides elaborated by two chemical methods namely the pyrolysis spray and the sol-gel dip - coating. Our study is first focused on the effect of solvent on the properties of thin CuO films. Thin CuO films were prepared by the pyrolysis spray method using two different solvents: water and methanol. The structural, microstructural, morphological and optical characterizations of CuO thin films were carried out. The crystalline structure analysis using the XRD diffraction technique shows three characteristic peaks (002), (111) and (020) of the monoclinic CuO phase. The position of the peaks are shifted to the lowest angles, indicating the effect of tensile stress in the prepared films. The micro-Raman analysis confirms the results of XRD. The SEM observation shows that the morphology of the film strongly depends on the nature of the used solvent. The optical characterization of CuO- (distilled
water) sample shows a low transmittance compared to that prepared with methanol. This behavior is attributed to the simultaneous effects of thickness and solvent. Then, our study has been focused on the effect of experimental parameters and the addition of metal oxides (ZnO and NiO) on the properties of TiO2 thin films prepared by the sol-gel method. The structural characterization by means of micro-Raman spectroscopy shows vibration modes corresponding to the anatase phase of TiO2. Thin TiO2films and its compounds are characterized by micro-Raman, SEM, m-lines and Uvvisible techniques. Micro-Raman analysis shows that the TiO2 thin films are characterized by the modes of vibration of the Anatase phase. ZnO and NiO cause the decay of TiO2 vibration modes. The SEM observation shows that the addition of ZnO pushes the crystalline degradation (amorphization) of the TiO2 anatase phase. While UV.Vis analysis shows an increase in the optical gap due to the effect of amorphization and Burstein-Moss. The waveguide measurements reveal simple guided modes in both polarizations (TE0 and TM0) in all samples from which the refractive index and the thickness are calculated. A decreasing refractive index profile was observed when ZnO and NiO are introduced into thin films of pure TiO2. The photocatalytic activity is evaluated by the degradation of MB. The obtained results show that the thin films of pure TiO2 are the best
photocatalytic materials.
Note de contenu : Liste des publications.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/SER7582.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11419 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité SER/7582 SER/7582 Thèse Bibliothèque principale Thèses Disponible
Titre : Elaboration et étude des couches minces d’oxyde d’étain Type de document : texte imprimé Auteurs : Mourad Khechba, Auteur ; Abderaheman Bouabellou, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 97 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : Couche mince SnO2 dopage Sol-Gel DRX AFM Spectroscopie Raman UV-Vis Ellipsométrie spectroscopique (SE) Thin films doping Raman spectroscopy UV-Visible Ellipsometry Spectroscopic الشرائح الرقيقة أكسيد القصدير التطعيم-سائل-جامد حيود الاشعة السينية مجهر القوة الذرية مطيافية رامان مطيافية الاشعة فوق البنفسجية والمرئية والمطياف الاهليجي Index. décimale : 530 Physique Résumé : This work is devoted to the development of the tin oxide thin films by the sol-gel method. The effect of the annealing temperature, the number of layers and the doping on the structural and optical properties of the films obtained were investigated. The obtained films are characterized by X-ray diffraction (DRX), RAMAN spectroscopy, atomic force microscopy (AFM), UV-Visible spectroscopy and ellipsometry spectroscopic. Raman spectroscopy results show that the SnO2 thin films are crystallizes in rutile phase. A good crystallization is observed after 3 coats. The results of optical characterization show that all the films are transparent (75 to 85% optical transmittance) in the visible and The energy band gap of all the samples lies in the range of 3.63eV– 3.89eV With regard to doping, undoped and doped tin oxide thin films (SnO2:Cd, SnO2:Al) were deposited by Sol Gel Dip Coating method on glass and silicon Si(100) substrates. The DRX shows that all the films deposited on glass substrates have an amorphous structure. On the other hand, the films deposited on Si (100) substrate crystallize in the rutile phase, with a preferential orientation along the axis (310). AFM observations of the surface show that the doping rate affects the roughness. The grain size and the roughness of the samples decrease with the increase of the doping concentration. The SnO2, SnO2:Cd and SnO2:Al thin films are transparent in the visible region and opaque in the ultraviolet region. The band gap, determined from the transmission spectra for the deposited films, also decreases with the increase in the doping rate (from 06 to 10% Cd, and from 04 to 06% Al). In addition, the increase of the cadmium and aluminum doping concentration causes a slight increase in the refractive index.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/KHE7337.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10987 Elaboration et étude des couches minces d’oxyde d’étain [texte imprimé] / Mourad Khechba, Auteur ; Abderaheman Bouabellou, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2018 . - 97 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : Couche mince SnO2 dopage Sol-Gel DRX AFM Spectroscopie Raman UV-Vis Ellipsométrie spectroscopique (SE) Thin films doping Raman spectroscopy UV-Visible Ellipsometry Spectroscopic الشرائح الرقيقة أكسيد القصدير التطعيم-سائل-جامد حيود الاشعة السينية مجهر القوة الذرية مطيافية رامان مطيافية الاشعة فوق البنفسجية والمرئية والمطياف الاهليجي Index. décimale : 530 Physique Résumé : This work is devoted to the development of the tin oxide thin films by the sol-gel method. The effect of the annealing temperature, the number of layers and the doping on the structural and optical properties of the films obtained were investigated. The obtained films are characterized by X-ray diffraction (DRX), RAMAN spectroscopy, atomic force microscopy (AFM), UV-Visible spectroscopy and ellipsometry spectroscopic. Raman spectroscopy results show that the SnO2 thin films are crystallizes in rutile phase. A good crystallization is observed after 3 coats. The results of optical characterization show that all the films are transparent (75 to 85% optical transmittance) in the visible and The energy band gap of all the samples lies in the range of 3.63eV– 3.89eV With regard to doping, undoped and doped tin oxide thin films (SnO2:Cd, SnO2:Al) were deposited by Sol Gel Dip Coating method on glass and silicon Si(100) substrates. The DRX shows that all the films deposited on glass substrates have an amorphous structure. On the other hand, the films deposited on Si (100) substrate crystallize in the rutile phase, with a preferential orientation along the axis (310). AFM observations of the surface show that the doping rate affects the roughness. The grain size and the roughness of the samples decrease with the increase of the doping concentration. The SnO2, SnO2:Cd and SnO2:Al thin films are transparent in the visible region and opaque in the ultraviolet region. The band gap, determined from the transmission spectra for the deposited films, also decreases with the increase in the doping rate (from 06 to 10% Cd, and from 04 to 06% Al). In addition, the increase of the cadmium and aluminum doping concentration causes a slight increase in the refractive index.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/KHE7337.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10987 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité KHE/7337 KHE/7337 Thèse Bibliothèque principale Thèses Disponible Elaboration et étude des propriétés des couches minces d’oxydes et de nanocomposites à base de TiO2. / Farida Medjaldi
Titre : Elaboration et étude des propriétés des couches minces d’oxydes et de nanocomposites à base de TiO2. Type de document : texte imprimé Auteurs : Farida Medjaldi, Auteur ; Abderaheman Bouabellou, Directeur de thèse Mention d'édition : 03/10/2020 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2020 Importance : 129 f. Format : 30 cm. Note générale : 1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : physique:Sciences des Matériaux TiO2 SnO2 TiO2 :SnO2 nanocomposite sol-gel guidage optique photocatalyse optical guidance photocatalysis اكسيد التيتان اكسيد القصدير الاكاسيد المركبة سائل-جامد التوجيه البصري التحفيز الضوئي Index. décimale : 530 Physique Résumé :
The present work consists in studying the structural, optical and photocatalytic properties of thin layers of oxide and nanocomposites based on TiO2 elaborated by the sol-gel method. The different samples are characterized by means of several techniques: X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), m_lines spectroscopy (optical guidance), UV-Visible spectrophotometry, and photoluminescence. The XRD results show that the pure TiO2 layers, prepared by using two different precursors, crystallize in a tetragonal anatase structure, and that the intensity of the diffraction peaks increases with the growth of the thickness of the layers. The pure SnO2 layers crystallize in the rutile phase (cassiterite). The micro-Raman analysis shows that the TiO2: SnO2 nanocomposites are characterized by the two phase-vibration modes anatase TiO2 and rutile TiO2. While the addition of SnO2 oxide leads to a decrease of the vibration modes of the TiO2 anatase phase and an increase in the intensity of the signals associated with the rutile TiO2. This means that SnO2 promotes and facilitates the growth of the TiO2 rutile at low temperatures, due to the fact that the TiO2 rutile has a structure identical to that of the SnO2 cassiterite phase. The SEM observations confirm the results obtained by Raman spectroscopie. The results obtained using UV-Visible spectrophotometry show that all the films are transparent in the visible and opaque in the UV, the transmission and the number of interference fringes of the TiO2: SnO2 layers decrease with increasing SnO2 concentration. The waveguiding measurements record the excitation of a single guided mode for the two polarizations TE0 and TM0 for all the samples. A decreasing profile of refractive index and of thickness is observed as the content of SnO2 increases. Photocatalytic tests are carried out on the degradation of the methylene blue (BM) under UV radiation. The obtained results show that the degradation efficiency of thin TiO2: SnO2 (8: 2) films is greater than that of pure TiO2 and SnO2 oxide films. Photoelectrochemical measurements show that the film of the SnO2: TiO2 (8: 2) nanocomposite exhibits the highest photocurrent response.
Note de contenu :
Annexes.Diplôme : Doctorat en sciences En ligne : ../theses/physique/MED7723.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11557 Elaboration et étude des propriétés des couches minces d’oxydes et de nanocomposites à base de TiO2. [texte imprimé] / Farida Medjaldi, Auteur ; Abderaheman Bouabellou, Directeur de thèse . - 03/10/2020 . - جامعة الإخوة منتوري قسنطينة, 2020 . - 129 f. ; 30 cm.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : physique:Sciences des Matériaux TiO2 SnO2 TiO2 :SnO2 nanocomposite sol-gel guidage optique photocatalyse optical guidance photocatalysis اكسيد التيتان اكسيد القصدير الاكاسيد المركبة سائل-جامد التوجيه البصري التحفيز الضوئي Index. décimale : 530 Physique Résumé :
The present work consists in studying the structural, optical and photocatalytic properties of thin layers of oxide and nanocomposites based on TiO2 elaborated by the sol-gel method. The different samples are characterized by means of several techniques: X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), m_lines spectroscopy (optical guidance), UV-Visible spectrophotometry, and photoluminescence. The XRD results show that the pure TiO2 layers, prepared by using two different precursors, crystallize in a tetragonal anatase structure, and that the intensity of the diffraction peaks increases with the growth of the thickness of the layers. The pure SnO2 layers crystallize in the rutile phase (cassiterite). The micro-Raman analysis shows that the TiO2: SnO2 nanocomposites are characterized by the two phase-vibration modes anatase TiO2 and rutile TiO2. While the addition of SnO2 oxide leads to a decrease of the vibration modes of the TiO2 anatase phase and an increase in the intensity of the signals associated with the rutile TiO2. This means that SnO2 promotes and facilitates the growth of the TiO2 rutile at low temperatures, due to the fact that the TiO2 rutile has a structure identical to that of the SnO2 cassiterite phase. The SEM observations confirm the results obtained by Raman spectroscopie. The results obtained using UV-Visible spectrophotometry show that all the films are transparent in the visible and opaque in the UV, the transmission and the number of interference fringes of the TiO2: SnO2 layers decrease with increasing SnO2 concentration. The waveguiding measurements record the excitation of a single guided mode for the two polarizations TE0 and TM0 for all the samples. A decreasing profile of refractive index and of thickness is observed as the content of SnO2 increases. Photocatalytic tests are carried out on the degradation of the methylene blue (BM) under UV radiation. The obtained results show that the degradation efficiency of thin TiO2: SnO2 (8: 2) films is greater than that of pure TiO2 and SnO2 oxide films. Photoelectrochemical measurements show that the film of the SnO2: TiO2 (8: 2) nanocomposite exhibits the highest photocurrent response.
Note de contenu :
Annexes.Diplôme : Doctorat en sciences En ligne : ../theses/physique/MED7723.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11557 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité MED/7723 MED/7723 Thèse Bibliothèque principale Thèses Disponible
Titre : Etude de l'interaction entre le Zirconium en couche mince et un substrat en acier Type de document : texte imprimé Auteurs : Karim Benouareth, Auteur ; Abderaheman Bouabellou, Auteur Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 239 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : Carbure de zirconium nitrure de zirconium couches minces nitruration pulvérisation cathodique traitement thermique diffusion nanodureté Zirconium carbide zirconium nitride thin films sputtering heat treatment nanohardness آربيدات الزرآونيوم نتريدات الزرآونيوم الشرائح الرقيقة النتردة الرش المهبطي المعالجة الحرارية الإنتشار نانوصلادة Index. décimale : 530 Physique Résumé : Thin films of zirconium carbides and nitrides have been elaborated by depositing the zirconium films by RF magnetron sputtering on high carbon steel EN C100 (1 %wt. of carbon) and nitrided EN C100 steel substrates, followed by a thermal annealing of the (coatings/substrates) systems. By activing the interstitials atoms (carbone, nitrogen) diffusing from the substrate to the film, the thermal annealing leads to the formation of hard coatings with good adhesion to the substrate and excellent mechanical properties. The influence of annealing temperature on the microstructural and mechanical properties and on the formed compounds in the thin films is elucidated.
The nitridation of substrates using a thermochemical technique by ionic plasma allows the formation of stœchiometric compound ZrN of the nitride, while only the under-stœchiometric compound ZrC0.6 of the carbide which is formed on the pristine substrate. The measured values of hardness and Young modulus are 28 GPa and 380 GPa for the nitride film against 18 GPa and 240 GPa respectively for the carbide film.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/BEN7272.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10853 Etude de l'interaction entre le Zirconium en couche mince et un substrat en acier [texte imprimé] / Karim Benouareth, Auteur ; Abderaheman Bouabellou, Auteur . - جامعة الإخوة منتوري قسنطينة, 2018 . - 239 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : Carbure de zirconium nitrure de zirconium couches minces nitruration pulvérisation cathodique traitement thermique diffusion nanodureté Zirconium carbide zirconium nitride thin films sputtering heat treatment nanohardness آربيدات الزرآونيوم نتريدات الزرآونيوم الشرائح الرقيقة النتردة الرش المهبطي المعالجة الحرارية الإنتشار نانوصلادة Index. décimale : 530 Physique Résumé : Thin films of zirconium carbides and nitrides have been elaborated by depositing the zirconium films by RF magnetron sputtering on high carbon steel EN C100 (1 %wt. of carbon) and nitrided EN C100 steel substrates, followed by a thermal annealing of the (coatings/substrates) systems. By activing the interstitials atoms (carbone, nitrogen) diffusing from the substrate to the film, the thermal annealing leads to the formation of hard coatings with good adhesion to the substrate and excellent mechanical properties. The influence of annealing temperature on the microstructural and mechanical properties and on the formed compounds in the thin films is elucidated.
The nitridation of substrates using a thermochemical technique by ionic plasma allows the formation of stœchiometric compound ZrN of the nitride, while only the under-stœchiometric compound ZrC0.6 of the carbide which is formed on the pristine substrate. The measured values of hardness and Young modulus are 28 GPa and 380 GPa for the nitride film against 18 GPa and 240 GPa respectively for the carbide film.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/BEN7272.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10853 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BEN/7272 BEN/7272 Thèse Bibliothèque principale Thèses Disponible
Titre : Etude des propriétés physiques des céramiques supraconductrices dopées : YBa2Cu3O7-δ. Type de document : texte imprimé Auteurs : Souheila Chamekhi, Auteur ; Abderaheman Bouabellou, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2019 Importance : 102 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : physique:Sciences des Matériaux SHTC YBCO Dopage DRX MEB Spectroscopie Raman Résistivité électrique Susceptibilité magnétique HTCS Doping XRD SEM Raman spectroscopy Electrical resistivity Magnetic Susceptibility الموصلات الفائقة الناقلية ذات الدرجة الحرجة العالية التمغنط الانعراج السيني المجهر الالكتروني أطياف Rama Index. décimale : 530 Physique Résumé : In order to study the effect of doping on the physical properties of superconducting YBa2Cu3O7-δ ceramic compound in which Cu was substituted by: Ni, Ag, Mn and Co. We have prepared our samples from carbonate BaCO3, oxides Y2O3, CuO, MnO2 and CoO and AgNO3, by the solid state reaction method. The samples were then characterized by beams of the techniques of X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive (EDX) analysis, Raman spectroscopy, electrical resistivity and DC susceptibility measurements. The analysis of the XRD shows the presence of the orthorhombic major phase YBa2Cu3O7-δ (YBCO) and the secondary phases BaCuO2 (Y011) and Y2BaCuO5 (Y211). No phase transition occurred at the atomic concentration dopants 0 x 4%. The refinement by Winplotr and Dicvol04 programs shows that the cell parameters have been affected, due to the incorporation of the dopant into the cell. The SEM micrographs show that the incorporation of all the dopants induces in generally a thinner grain with a porous structure, except for some samples that have large grains. The EDX analysis confirms the incorporation of the dopants into the grains. This analysis reveals also that the distribution dopants in the samples is not homogenous. These analyses allow to suggest the possibility of substitution of Ag and Mn in barium sites and copper chain sites Cu(1). Measurements of DC magnetic susceptibility and electrical resistivity reveal a decrease in TCon as a function of the doping rate. This decrease is more probably due to the change in carrier density, CuO2 plane disorder and overall oxygen content, for nickel and manganese. This is not the case for the silver doped sample with 0.5 at.% which has a greater TC than the pure sample. The results of the Raman spectroscopy confirm the presence of the YBCO phase with the two secondary Y011 and Y211 phases. The incorporation of the dopant in the grains in the Cu (2) planar sites, and the contraction of the parameter c. The recorded five active modes confirm that the structure is orthorhombic for all the samples and the phase transition has not take place in the interval 0 x 4%. Diplôme : Doctorat en sciences En ligne : ../theses/physique/CHA7504.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11337 Etude des propriétés physiques des céramiques supraconductrices dopées : YBa2Cu3O7-δ. [texte imprimé] / Souheila Chamekhi, Auteur ; Abderaheman Bouabellou, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2019 . - 102 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : physique:Sciences des Matériaux SHTC YBCO Dopage DRX MEB Spectroscopie Raman Résistivité électrique Susceptibilité magnétique HTCS Doping XRD SEM Raman spectroscopy Electrical resistivity Magnetic Susceptibility الموصلات الفائقة الناقلية ذات الدرجة الحرجة العالية التمغنط الانعراج السيني المجهر الالكتروني أطياف Rama Index. décimale : 530 Physique Résumé : In order to study the effect of doping on the physical properties of superconducting YBa2Cu3O7-δ ceramic compound in which Cu was substituted by: Ni, Ag, Mn and Co. We have prepared our samples from carbonate BaCO3, oxides Y2O3, CuO, MnO2 and CoO and AgNO3, by the solid state reaction method. The samples were then characterized by beams of the techniques of X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive (EDX) analysis, Raman spectroscopy, electrical resistivity and DC susceptibility measurements. The analysis of the XRD shows the presence of the orthorhombic major phase YBa2Cu3O7-δ (YBCO) and the secondary phases BaCuO2 (Y011) and Y2BaCuO5 (Y211). No phase transition occurred at the atomic concentration dopants 0 x 4%. The refinement by Winplotr and Dicvol04 programs shows that the cell parameters have been affected, due to the incorporation of the dopant into the cell. The SEM micrographs show that the incorporation of all the dopants induces in generally a thinner grain with a porous structure, except for some samples that have large grains. The EDX analysis confirms the incorporation of the dopants into the grains. This analysis reveals also that the distribution dopants in the samples is not homogenous. These analyses allow to suggest the possibility of substitution of Ag and Mn in barium sites and copper chain sites Cu(1). Measurements of DC magnetic susceptibility and electrical resistivity reveal a decrease in TCon as a function of the doping rate. This decrease is more probably due to the change in carrier density, CuO2 plane disorder and overall oxygen content, for nickel and manganese. This is not the case for the silver doped sample with 0.5 at.% which has a greater TC than the pure sample. The results of the Raman spectroscopy confirm the presence of the YBCO phase with the two secondary Y011 and Y211 phases. The incorporation of the dopant in the grains in the Cu (2) planar sites, and the contraction of the parameter c. The recorded five active modes confirm that the structure is orthorhombic for all the samples and the phase transition has not take place in the interval 0 x 4%. Diplôme : Doctorat en sciences En ligne : ../theses/physique/CHA7504.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11337 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité CHA/7504 CHA/7504 Thèse Bibliothèque principale Thèses Disponible
