INSTITUTE :UIE

DEPARTMENT: ALL ACADEMIC UNITS

Bachelor of Engineering (All Sections)
Subject Name and Code:
Engineering Physics 23SPH-141
Prepared by: Arminder Kaur, Assistant Prof. Physics

UNIT 2
CRYSTALLOGRAPHY & ULTRASONICS DISCOVER . LEARN . EMPOWER
 COURSE OBJECTIVES
1. The course is designed to make the students industry ready to contribute in the
growing demand of the industry at local, national and international level.
2. It will make the students competent to understand basic concepts and
applications of advanced engineering physics and apply its principles in their
respective fields at global platform.
3. It will enhance the skill level of the students and shall make them preferred
choice for getting employment in industry and research labs.
4. It will give thorough knowledge of the discipline to enable students to
disseminate knowledge in pursuing excellence in academic areas.

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 Course Outcomes

CO Title Level
Number On completion of this course, the students are expected
to learn

CO1 Quote the basic fundamental concepts of lasers, optical Remember,

fibres, crystallography, ultrasonic oscillations, semiconductor
Understand
physics, quantum mechanics and nanotechnology.

CO2 Demonstrate the working of various lasers, fibre Understand

components, semiconductor devices; explain the behaviour
of crystalline solids, quantum and nano-scale systems.

CO3 Solve problems by applying principles related to lasers, Applying

fibres, semiconductors, oscillations, quantum and
nanoscience.

CO4 Compare various lasers and fibres, semiconducting devices, Analyze

crystalline materials, structures at quantum and nanoscale
on the basis of their properties for industrial applications.

CO5 Develop various systems using lasers, fibres, semiconductors Design

and nanomaterials for futuristic applications.

Figure 1.1 Manufacturing of semiconductor3[1]

 INTRODUCTION
UNIT -2

CHAPTER 1
CRYSTALLOGRAPHY &
ULTRASONICS

TOPIC: Basic terms, types of crystal systems,

Bravais lattices
 LECTURE OBJECTIVE

Students will understand

Students will learn about Students will learn basic
how arrangements effect
crystallography branch terms related to
the properties of
and its importance. crystallography
materials.

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 CONTENT

INTRODUCTION TO CRYSTALLOGRAPHY
TYPES OF MATTER-SOLID, LIQUID, GAS
TYPES OF SOLIDS
PROPERTIES
CRYSTAL STRUCTURE
SPACE LATTICE
BASIS
UNIT CELL
BRAVAIS LATTICE
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 TYPES OF MATTER
Solids
In the solid state the vibrating particles
form a regular pattern. This explains the
fixed shape of a solid.
Liquids
In a liquid the particles still touch their
neighbors but they move around, sliding TYPES OF PHYSICAL STATES
over each other.
Gases
In the gas state, widely-spaced particles
move around randomly. This explains
why you can compress gases.

Figure 1.2 Types of matter and their basic properties

[2]
 TYPES OF SOLIDS
A crystal or crystalline solid is a
solid material whose constituents
are arranged in a highly ordered
microscopic structure, forming a
crystal lattice that extends in all
directions. For e.g. metals
An amorphous or non-
crystalline solid is a solid that
lacks the long-range order that is
characteristic of a crystal for e.g.
Glass-Ceramics.

Figure 1.3 describing crystal and amorphous solid structure [3]

 PROPERTIES
Geometry:
Crystalline Solids – Particles are arranged in a repeating pattern. They have a regular and
ordered arrangement resulting in a definite shape.
Amorphous Solids – Particles are arranged randomly. They do not have an ordered
arrangement resulting in irregular shapes.
Melting Points
Crystalline Solids – They have a sharp melting points.
Amorphous Solids – They do not have sharp melting points. The solid tends to soften
gradually over a temperature range.
Isotopism:
Crystalline Solids – Anisotropic in nature. i.e., the magnitude of physical properties (such
as refractive index, electrical conductivity, thermal conductivity etc.) is different along
with different directions of the crystal.
Amorphous Solids – Isotropic in nature. i.e., the magnitude of the physical properties is
the same along with all directions of the solid.
 PROPERTIES
Cleavage Property
Crystalline Solids – When cutting with a sharp edge, the two new halves will have
smooth surfaces.
Amorphous Solids – When cutting with a sharp edge, the two resulting halves will
have irregular surfaces.
Rigidity:
Crystalline Solids – They are rigid solids and applying mild forces will not distort
its shape.
Amorphous Solids – They are not rigid, so mild effects may change the shape.

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 FORMATION OF CRYSTAL
STRUCTURE

 Space lattice +
basis = crystal
structure
 Space lattice
 Basis

Figure 1.4 crystal structure consisting basis and space lattice [4]
 Space lattice

SPACE LATTICE- a regular,

indefinitely repeated array of
points in three dimensions in
which the points lie at the
intersections of three sets of
parallel equidistant planes.
BASIS-The crystal basis is
defined by the type, number,
and arrangement of atoms
inside the unit cell.

Figure 1.5 space lattice and basis [5]

CRYSTAL STRUCTURE

Figure 1.6 crystal structure by joining space lattice and basis [6]
 UNIT CELL

The smallest group of

atoms which has the
overall symmetry of a
crystal, and from
which the entire
lattice can be built up
by repetition in three
dimensions.

Figure 1.7 unit cell [7]

 PRIMITIVE UNIT CELL

A primitive cell is a unit cell that contains

exactly one lattice point. It is the smallest
possible cell. If there is a lattice point at
the edge of a cell and thus shared with
another cell, it is only counted half.
Accordingly, a point located on the corner
of a cube is shared by 8 cubes.

Figure 1.8 primitive unit cell [7]

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 NON-PRIMITIVE CELL

Non-primitive cells are of three kinds:

 end-centered : an extra lattice point is centered in
each of two opposing faces of the cell
 face-centered : an extra lattice point is centered in
every face of the cell
 body-centered : an extra lattice point is centered in
the exact middle of the cell
 They have larger volume than primitive unit cell.

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 NON-PRIMITIVE UNIT CELL

Figure 1.9 Body centred cell [8] Figure 1.10 Face centred cell [8] Figure 1.11 end centred cell [8]
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 LATTICE PARAMETERS

6 parameters
Length of axis along x, y, z
axis written as a, b, c
Angle between y and z axis
is α
Angle between x and z axis
is β
Angle between x and y
axis is γ

Figure 1.12 parameters of unit cell [9]

CRYSTAL SYSTEMS

Figure 1.13 Crystal systems [8]

 APPLICATIONS IN ENGINEERING

X-ray crystallography is a powerful non-

destructive technique for determining
the molecular structure of a crystal.

It was primarily used in fundamental

science applications for determining the
size of atoms, the lengths and different
types of chemical bonds, the atomic
arrangement of materials.

Figure 1.14 x-ray experiment set up [10] 20

 APPLICATIONS

The difference between materials at the

atomic level, and for determining the
crystalline integrity, grain orientation, grain
size, film thickness and interface roughness
of alloys and minerals.

It is now often used to identify the structure

of various biological materials, vitamins,
pharmaceutical drugs, thin-film materials
and multi-layered materials. It has become
one of the standard ways of analyzing a
material.

Figure 1.15 bacteria image [11] 21

 LIMITATIONS OF X-Ray DIFFRACTION

As the crystal's repeating unit, its unit cell, becomes larger and more complex, the
atomic-level picture provided by X-ray crystallography becomes less well-
resolved for a given number of observed reflections.
If the diffraction pattern is not clear, then the sample may not be pure and will be
purified at this point. But other factors can prevent a diffraction pattern from
being generated including a too-small sample (needs to be at 0.1 nm in each
dimension), an irregular crystal structure, and the presence of any internal
imperfections—such as cracks—in the crystal.

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 FREQUENTLY ASKED QUESTIONS
1. Justify use of X-Ray to study crystal structure.
2. Is there any term like polycrystalline?
3. Differentiate between crystalline and amorphous materials.
4. Explain non primitive unit cell
5. Define unit cell, space lattice, basis.
6. How many crystal systems are there and describe them.
7. Predict the unit cell for NaCl

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 SUMMARY
Crystallography is a field of science that deals with arrangements of atoms.

There are three types of matter of state.

Crystalline materials are those have periodic arrangements of atoms.

Space lattice and basis form complete crystal.

Unit cell is smallest repeating unit in crystals.

There are 6 parameters of one unit cell.

There are 7 crystal systems and 14 Bravais lattice.

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 REFERENCES
https://ocw.mit.edu/courses/materials-science-and-engineering/3-091sc-introducti
on-to-solid-state-chemistry-fall-2010/amorphous-materials/21-introduction-to-gla
sses/
https://www3.nd.edu/~amoukasi/CBE30361/Lecture__crystallography_A.pdf
http://www.uvm.edu/~gdrusche/Classes/GEOL%20110%20-%20Earth%20Materi
als/2010%20files/Lecture%2011%20-%20Crystallography.pdf
https://www.slideshare.net/AvinashAvi110/crystallography-125579803
http://ctc.xmu.edu.cn/jiegou/ppt/chapter7.pdf

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 REFERENCE BOOKS
http://indico.ictp.it/event/a10148/session/22/contribution/16/material/0/0.pdf
http://www.teqipiitk.in/workshop/2016/xrd/ppt/Prof%20Rajesh/crystallograp
hy.pdf
http://users.encs.concordia.ca/~mmedraj/TMG-Library/books/Crystallograph
y_and_the_World_of_Symmetry.pdf
http://alpha.science.unitn.it/~rx/Dakar_school/1_Fornasini_a_cryst.pdf
Malik H.K, Singh A.K. (2011) Engineering Physics, TMH, New Delhi.
ISBN: 9780070671539
T2. Beiser A. (2002) Concepts of Modern Physics, McGraw Hill Education.
ISBN: 9780070495531

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 REFERENCE VIDEOS
https://study.com/academy/lesson/unit-cell-lattice-parameters-cubic-structure
s.html
https://nptel.ac.in/courses/104/106/104106093/
https://www.coursera.org/lecture/materials-science/crystallography-and-the-e
lectron-microscope-YhPAB
https://www.youtube.com/watch?v=yooD_MZgQN4
https://www.youtube.com/watch?v=cm9W10Kg8q4
https://www.youtube.com/watch?v=2KWjYQnHDKA
https://www.youtube.com/watch?v=6c6ItfyiNcs

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 IMAGES REFERENCES
[1] https://fortune.com/2020/06/30/america-tech-semiconductor-manufacturing-investment/
[2] https://www.grc.nasa.gov/www/k-12/airplane/state.html
[3] https://www.britannica.com/science/amorphous-solid
[4] https://www.pngwing.com/en/free-png-yywbt
[5] https://users.aber.ac.uk/ruw/teach/334/bravais.php
[6]
https://www.uio.no/studier/emner/matnat/fys/MENA3100/v18/leture-slides/introduction-to-
crystallography.pdf
[7]
https://www.examfear.com/notes/Class-12/Chemistry/The-Solid-State/1060/Primitive-Unit-
Cells.html
[8]
https://thefactfactor.com/facts/pure_science/chemistry/physical-chemistry/bravais-lattices/7
443/
[9] https://www.doitpoms.ac.uk/tlplib/crystallography3/parameters.php 28
THANK YOU

For queries
Email: arminder.uis@cumail.in