Atomic Diffusion in Glasses Studied with Coherent X-Rays (eBook)

Manuel Ross (Autor)

eBook Download: PDF

2016 | 1st ed. 2016
XVIII, 111 Seiten
Springer International Publishing (Verlag)
978-3-319-28646-4 (ISBN)

Infos

This thesis provides the first successful study of jump diffusion processes in glasses on the atomic scale, utilizing a novel coherent technique. This new method, called atomic-scale X-ray Photon Correlation Spectroscopy or aXPCS, has only recently been proven to be able to capture diffusion processes with atomic resolution in crystal systems.

With this new toolkit for studying atomic diffusion in amorphous systems, new insight into basic processes in a wide range of technically relevant materials, like fast ionic conductors, can be obtained.

Inhalt

Parts of this thesis have been published in the following journal article: 6
Supervisor’s Foreword 7
Abstract 9
Acknowledgements 10
Contents 12
Abbreviations 15
1 Introduction 17
1.1 A Long-Standing Challenge: Gaining Insight into Glass Fundamentals 17
1.1.1 Glass Structure 18
1.1.2 Glassy Dynamics 20
1.2 A New Method for Studying Dynamics: aXPCS 21
1.2.1 Methods for Studying Diffusion 21
1.2.2 The Development of aXPCS 23
References 26
2 Theory 29
2.1 Achieving Coherent Scattering 29
2.1.1 Scattering Intensity and Speckle Patterns 29
2.1.2 Optimal Scattering Thickness 32
2.1.3 Coherence Properties 34
2.2 Deducing Real-Space Time-Correlations from Intensity Pattern Series 38
2.2.1 Van Hove Pair Correlation Function 39
2.2.2 Autocorrelation Functions 39
2.2.3 Link Between Autocorrelation Functions of Measured Intensities and Those of Real-Space Information 41
2.3 Unravelling Atomic Dynamics 42
2.3.1 Continuous Diffusion 43
2.3.2 Jump Diffusion: Chudley--Elliott Model 44
2.3.3 Extensions of the Chudley--Elliott Model 47
2.4 Applying aXPCS to Diffusion in Glasses 48
2.4.1 Influence of Different Scattering Species 48
2.4.2 Kohlrausch Exponent 49
2.4.3 Short-Range Order Correction 50
References 51
3 Experimental 53
3.1 Preparing Glass Samples for Coherent Experiments 53
3.1.1 Glass Melting 53
3.1.2 Creating Thin But Stable Samples: Dimpling Grinder 55
3.2 Creating a Stable Sample Environment for Atomic-Resolution Measurements 58
3.2.1 Vacuum Sample Cell 58
3.2.2 Helium Cryostat 62
3.3 Obtaining Scattering Data for Atomic-Diffusion Studies 62
3.3.1 Generating Coherent X-Rays 62
3.3.2 Conducting Synchrotron Experiments 65
3.3.3 Gaining Complementary X-Ray Scattering Information 69
References 70
4 Data Analysis 71
4.1 Converting Scattered X-Rays to Intensity Data 71
4.1.1 Detecting Single Photons 72
4.1.2 Disposing of the Dark Current 73
4.2 Obtaining Correlation Times from Intensity Data 74
4.2.1 Histogram 74
4.2.2 Droplet Algorithm 75
4.2.3 Autocorrelation 77
4.2.4 Two-Time Correlation 78
4.3 Extracting Dynamics from Correlation Times 79
4.4 Evaluating in Real-Time During Experiments 80
References 80
5 Proof of Concept: Direct Observation of Atomic Diffusion in Glasses 82
5.1 Previous Studies of Lead Silicate Glasses 82
5.1.1 Structure 82
5.1.2 Dynamics 85
5.2 New Insight into Lead Silicate Glasses 86
5.2.1 Scattering Intensities 86
5.2.2 Glass Temperatures 87
5.2.3 Atomic Dynamics 88
References 94
6 Practical Application: Tailoring Fast Ionic Diffusion 96
6.1 Previous Studies on Amorphous Fast Ionic Conductors 97
6.1.1 Structure of Alkali Borate Glasses 97
6.1.2 Atomic Dynamics 98
6.2 Tailoring Atomic Diffusion in Glasses 100
6.2.1 Fluorescence: Caesium Borate Glasses 100
6.2.2 Influence of Thermal History: Rubidium Borate Glasses 102
6.2.3 Path to Light Alkali: Potassium Borate Glasses 107
6.2.4 First Measurement of Light-Alkali Diffusion: Sodium Borate Glasses 109
References 111
7 Conclusion 113
References 115
Appendix A 116

Produkt-Details

• Erscheint lt. Verlag: 13.1.2016
• Reihe/Serie: Springer Theses
• Reihe/Serie: Springer Theses
• Zusatzinfo: XVIII, 111 p. 67 illus., 22 illus. in color.
• Verlagsort: Cham
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Chemie ► Physikalische Chemie
• Themenwelt: Naturwissenschaften ► Physik / Astronomie
• Themenwelt: Technik ► Maschinenbau
• Schlagworte: Atomic-scale X-ray Photon correlation spectroscopy • aXPCS • Coherent X-ray Scattering • Detecting atomic diffusion • Fast ionic conductors • Fast ionic diffusion • Lead silicate glass • Rubidium borate glass • Synchroton study of diffusion in glass • XPCS
• ISBN-10: 3-319-28646-3 / 3319286463
• ISBN-13: 978-3-319-28646-4 / 9783319286464