X-Ray Diffraction for Materials Research

From Fundamentals to Applications

Myeongkyu Lee

• Publisher: Apple Academic Press
• Year: 2017
• ISBN:
  9781315359847
• Edition: 1
• Topic: Scienze biologiche
• Subtopic: Scienza generale

X-ray diffraction is a useful and powerful analysis technique for characterizing crystalline materials commonly employed in MSE, physics, and chemistry. This informative new book describes the principles of X-ray diffraction and its applications to materials characterization. It consists of three parts. The first deals with elementary crystallography and optics, which is essential for understanding the theory of X-ray diffraction discussed in the second section of the book. Part 2 describes how the X-ray diffraction can be applied for characterizing such various forms of materials as thin films, single crystals, and powders. The third section of the book covers applications of X-ray diffraction.

The book presents a number of examples to help readers better comprehend the subject. X-Ray Diffraction for Materials Research: From Fundamentals to Applications also

• provides background knowledge of diffraction to enable nonspecialists to become familiar with the topics

• covers the practical applications as well as the underlying principle of X-ray diffraction

• presents appropriate examples with answers to help readers understand the contents more easily

• includes thin film characterization by X-ray diffraction with relevant experimental techniques

• presents a huge number of elaborately drawn graphics to help illustrate the content

The book will help readers (students and researchers in materials science, physics, and chemistry) understand crystallography and crystal structures, interference and diffraction, structural analysis of bulk materials, characterization of thin films, and nondestructive measurement of internal stress and phase transition.

Diffraction is an optical phenomenon and thus can be better understood when it is explained with an optical approach, which has been neglected in other books. This book helps to fill that gap, providing information to convey the concept of X-ray diffraction and how it can be applied to the materials analysis.

This book will be a valuable reference book for researchers in the field and will work well as a good introductory book of X-ray diffraction for students in materials science, physics, and chemistry.

PART I

X-RAYS AND CRYSTAL GEOMETRY

CHAPTER 1

ELECTROMAGNETIC WAVES AND X-RAYS

CONTENTS

1.1. Materials Analysis by ‐Ray Diffraction

1.2. Electromacnetic Spectrum

1.3. Wave‐Particle Duality

1.4. Generation of X‐Rays

1.5. Absorption

Problems

1.1. MATERIALS ANALYSIS BY X-RAY DIFFRACTION

X‐rays refer to the electromagnetic radiations that have a wavelength range of 10⁻³ nm to 10 nm. X‐rays, discovered by W. Röntgen in 1895, were so named because their characteristics were unknown at that time. Today, X‐rays are widely used to image the inside of visually opaque objects, for example, in medical radiography, computed tomography, and security scanners. X‐rays can also reveal various information on the materials, including crystal structure, phase transition, crystalline quality, orientation, and internal stress. This is made possible as a consequence of the interaction between X‐rays and matter. X‐rays with wavelengths below 0.10.2 nm are called hard X‐rays, while those with longer wavelength are called soft X‐rays. The X‐rays utilized for materials analysis are hard X‐rays. There are two reasons why X‐rays are so powerful for analyzing the internal state of crystalline materials. First, hard X‐rays are deeply penetrating into all substances, although the penetration depth varies with the substance. While metals are optically opaque, they may be transparent or translucent to the hard X‐rays. Secondly, X‐rays have much shorter wavelengths than visible light. This makes it possible to probe small structures that cannot be seen under an ordinary microscope. In particular, hard X‐rays have wavelengths similar to the size of atoms. Therefore, they can be diffracted by atoms periodically arranged within the substance. Monitoring the diffraction direction and intensity allows the internal structure of crystalline matters to be revealed at the atomic level.

The diffraction of light had already been known before X‐rays were discovered. Diffraction refers to various phenomena that occur when a wave encounters an obstacle or a slit. In classical physics, the diffraction phenomenon is described as the bending of waves around small obstacles and the spreading out of waves passing through small openings. Diffraction occurs with all waves, including sound wave, water wave, and electromagnetic waves, such as visible light, X‐rays, and radio waves. It is well known that when a light wave is confronted with a periodic structure, it is split into several waves traveling in different directions. This behavior is also called diffraction, in which the periodic structure plays a role of diffraction grating. The diffraction effect becomes most profound when the wavelength is comparable to the grating period. Most materials are crystalline with regularly arranged atoms and X‐rays have wavelengths similar to the interatomic distances. A crystalline matter contains many atomic planes of different orientation and spacing, each of which contact as an effective diffraction grating when an X‐ray beam is incident. The diffraction pattern, characterized by the direction and intensity of the diffracted beams, is characteristic of the matter and its internal structure. X‐ray diffraction is a very powerful, nondestructive tool for analyzing materials and a variety of information can be deduced from the obtained diffraction pattern.

This book deals with the principle and applications of X‐ray diffraction and the Chapters 1 and 2 are concerned with the general properties of electromagnetic waves and the geometry of crystals, respectively. X-ray diffraction is a consequence of the interplay between electromagnetic radiation and periodic atoms. Therefore, some knowledge on these topics is e...