The document discusses neutron diffraction, a technique used for determining atomic and magnetic structures of materials, and compares it with X-ray diffraction (XRD). It outlines the principles, instrumentation, and various applications of neutron diffraction while highlighting its advantages over XRD, such as better detection of light elements and magnetic structures. The future of neutron diffraction is promising, with increasing demand in material structure research and advancements aimed at exploring new technologies for electrical energy storage.

1. NEUTRON DIFFRACTION
Presented by-
Nirmal Urma
Jayashree Sa
Rajashree khatua

2. Contents-
• Introduction
• XRD
• Neutron Diffraction
• Principle
• Instrumentation
• Working
• Application
• Future

3. Introduction-
• A phenomena that occurs when a wave encounters
an obstacle
• When collimated beam of waves strikes pair of
parallel lattice planes in a crystal, each atom acts as
a scattering center
• The secondary waves from the diffraction interfere
with each other to produce diffracted images
• Three types of diffraction techniques
- XRD
- Neutron diffraction
- Electron diffraction

4. XRD-
• XRD is a common analytical technique used for the study of
crystal structures and atomic spacing. It is used to identify
the degree of crystallinity of a material which provides
information on unit cell dimension. This technique is based
on the principle of interference.
• XRD has size limitation. It is much more accurate for
measuring large crystalline structures rather than small
ones.
• It does not interact strongly with lighter elements.
• It is relatively low in sensitivity.
• It cannot explain the magnetic properties.

5. Why neutrons?
- Wave length comparable with inter atomic spacing
- Kinetic energy is comparable with the interaction
energy in solid
- Isotopic sensitivity allows contrast variation
- Neutrons has both wave and particle properties
- Penetrating => bulk properties are measured
- Neutron possesses spin

6. Neutron diffraction-
• Neutron diffraction is the application of neutron
scattering to the determination of the atomic
and/or magnetic structure of a material. It can
be equally well applied to study crystalline solid,
gases, liquids or amorphous materials.
• The technique is similar to X-ray diffraction but
the different type of radiation gives
complementary information.
• As neutrons have high penetration depth are
suited for the analysis of bulk samples.

7. XRD vs NEUTRON DIFFRACTION
NEUTRON DIFFRACTION
 Neighbours and isotopes
can be discriminated
 Light elements can be
detected
 Magnetic structures can be
investigated
 Lower absorption
XRD
 Neighbours and isotopes
cannot be discriminated
 Light elements hard to detect
 Magnetic properties cannot
be investigated
 Strong absorption

8. Different modes in neutron scattering-
1. Nuclear scattering-
It involves the interaction of a neutron with
the nucleus of the atom, so scattering is isotopic
2. Magnetic scattering-
It involves the interaction of a neutron with
the extended atomic electron distribution, so
the form factor is more like that seen for XRD
and it revels the microscopic magnetic structure
of material
 The magnetic scattering length is comparable to
the nuclear scattering length, i.e the magnetic
and nuclear signals have comparable strengths.

9. Importance-
• Nuclear neutron scattering:
- Elastic scattering
diffraction-crystal structure
- Inelastic scattering
excitations-phonons
• Magnetic neutron scattering:
-Elastic scattering
diffraction- spin structure
-Inelastic scattering
Excitations- magnons

10. Principle-
• When a monochromatic radiation fall on sample,
the diffraction from a Bragg plane results in the
form of a cone ( Debye Scherer cone) with angle
2θ.
• The diffracted beam is shaped using suitable optical
devices. The intensity profile is recorded in the
detector.

11. Instrumentation-
• Neutron source- produce neutrons
• Monochromator
• Diffractometer or spectrometer
-allows neutron to interact with sample
- sorts out discrete wave length by monochromator
• Detector- detectors pick up neutrons scattered from
sample
• Analysis methods to determine material properties
• Brain power to interpret results

13. Working-
• This techniques requires a source of neutron. Neutrons
usually produced in a nuclear reactor or spallation
source.
• The source of neutron passed through the
monochromator , the monochromatized beam is
subjected to fall on diffractometer.
• Filters are also used to select desired neutron
wavelength.
• The sample is placed within a neutron beam and the
angles at which the neutrons are deflected or scattered
by the material are recorded to generate a “diffraction
pattern” from which structural information can be
extracted.

15. Application-
Used for determination of structure
Locating light atoms
Heavy atoms that absorb x-ray strongly
Similar atomic no/ isotopes
Magnetic properties
Single crystal study analysis
Inelastic scattering used for study of atomic
vibration and other excitations

16. Future of neutron diffraction-
• Neutron diffraction is now a tried-and tested
technique in strong demand by researchers
investigating the structure of material.
• Neutron diffraction is also being used to develop
technologies for electrical energy storage :
researchers are investigating the light elements
present in compounds suitable for ion exchange
systems.
• As the technique advances and wider ranges of
temperature and pressure are incorporated , the
research condition will improve, opening the
doors for new investigation.