EFFET DU DOPAGE SUR LA MODULATION DE STRUCTURE
DES MATERIAUX SUPRACONDUCTEURS A HAUTE
TEMPERATURE CRITIQUE A BASE DE BISMUTH.
REPUBLIQUE ALGERIENNE DEMOCRATIQUE ET POPULAIR MINISTERE DE L’ENSEIGNEMENT SUPERIEUR ET DE LA
RECHERCHE SCIENTIFIQUE
N° d’ordre: N° N° de Serie:
UNIVERSITE ECHAHID HAMMA LAKHDAR – EL OUED FACULTE DES SCIENCES EXACTES
DEPARTMENT DE PHYSIQUE
THESE Présentés par :
MIMOUNI MOURAD
En vue de l’obtenion du diplôme de doctorat en sciences Spécialité : Physique
OPTION: CRISTALLOGRAPHIE
TITRE
Soutenue le : 28 Décembre 2020
Devant le jury
Nom et Prénom
Grade
Affiliation
Position
Soria ZEROUAL
M.C.A Université d’El Oued PrésidentMohammed Sadok MAHBOUB
M.C.A Université d’El Oued RapporteurMohammed Fayçal MOSBAH
Professeur Ecole Nationale Polytechnique de ConstantineCo- Rapporteur
Azzeddine BEGGAS
M.C.A Université d’El Oued ExaminateurFayçal CHEMAM
Professeur Université Larbi Tebessi – TebessaExaminateur
Linda AISSANI
M.C.A Université Abas Laghrour -Khenchela
Table of contents
Content Page
Abstract I
List of figures IV
List of tables VIII
List of symbols IX
List of abbreviations XI
GENERAL INTRODUCTION
Preamble 2
Interest of superconductor 4
Objectives of the thesis 6
Thesis structure 7
Chapter I: Generalities on superconductivity
I-1 Basic Properties of a superconductor 9
I-1-1 Zero resistance 9
I-1-2 Meissner effect 10
I-1-3 Critical superconducting values 12
I-1-3-1 Critical temperature 12
I-1-3-2 Critical magnetic field 13 I-1-3-3 Critical current density Jc: 14
I-1-3-4 Critical Area 14
I-1-4 Energy gap 15
I-2 The major theories of Superconductivity 16
I-2-1 Theory of London 16
I-2-2 Ginzburg-Landau theory 18
I-2-2-1 Characteristic lengths 19 I-2-2-2 Magnetic flux quantification 21 I-2-3 Bardeen-Cooper-Schrieffer Theory (BCS theory) 23 I-3 Classification of superconductors 24
I-3-2 Type II superconductors 25
I-4 Vortex 27
I-4-1 Definition 27
I-4-2 Lorentz force and anchoring vortices 29 I-5 Flux flow, flux creep and thermally activated flux flow (TAFF) 31
I-6 Josephson effect 33
I-7 Weak Links 34
Chapter II: Bi-based superconductors
II-1 Introduction 36
II-2 Families of Superconductive Cuprates 36 II-3 Crystal Structures of Bi- superconductors
II-3-1 Introduction 39
II-3-2 The crystal Structures of Bi-22(n−1)n high temperature superconductors 40 II-4 Modulated structure of Bi-based superconductors 47 II-4-1 Modulated structure materials 47 II-4-2 Modulation in the Bi-2212 structure 49 II-4-3 Origin of the modulated structure 50 II-5 Effect of doping on the Bi-based superconductors 52 II-5-1 Introduction 52 II-5-2 Effect of doping on the Bi-2212 Phase 53 II-5-3 Effect of samarium doping on BSCCO 54 II-5-4 Effect of doping in Bi-sites of Bi-2212 phase 55 III-5-5 Effect of Oxygen stoichiometry 56
Chapter III: Samples preparation and characterization techniques
III-1 Introduction 58
III-2 Dry routes 59
III-2-1 Solid state reaction 59
III-2-2 Mechanical Ball-Milling Method 59 III-2-3 High Energy Ball-Milling Method 60 III-2-4 Powder-in-tube method (OPIT) 60
III-3-1 Auto-combustion Method 62
III-3-2 Sol-gel Method 63
III-3-3 Pechini method 66
III-3-4 Co-precipitation Technique 68
III-4 Samples Preparation 70
III-4-1 La series samples preparation 70 III-4-2 Sm series samples preparation 72 III-5 Characterization Techniques 74
III-5-1 FTIR spectroscopy 74
III-5-2 X-ray diffraction analysis 76
III-5-3 SEM analysis 79
III-5-4 EDX analysis 79
III-5-5 Thermogravimetric analysis 81 III-5-6 Resistivity and magneto-resistance measurements 83
Chapter IV: Results and discussions
IV-1 Introduction 87
IV-2 La series 88
IV-2-1 X-ray diffraction results 88 IV-2-2 Thermogravimetric results 95 IV-2-3 Scanning electron microscopy results 96 IV-2-4 Energy dispersive X (EDX) results 99
IV-3 Sm series 100
IV-3-1 FTIR spectroscopy results 100 IV-3-2 X-ray diffraction results 105 IV-3-3 Microstructure and EDX analysis results 113 IV-3-4 Resistivity and magneto-resistivity measurements results 116
General Conclusion & pespectives 122
References 125
Annex – A - Steps of Le Bail refinement using Jana 2006 program. 140
Publications 145
