(NS) Magnetism - PHY00056H

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  • Department: Physics
  • Module co-ordinator: Prof. Sarah Thompson
  • Credit value: 10 credits
  • Credit level: H
  • Academic year of delivery: 2019-20
    • See module specification for other years: 2018-19

Related modules

Co-requisite modules

  • None

Prohibited combinations


Additional information

Please note, the module requires some knowledge of crystal structures, electron densities of states and band structures such as covered in the pre-requisite Solid State I module and Stage 2 Statistical Mechanics. Natural Science students who have not taken these modules, are still welcome, and will be supported by directed reading and an optional additional tutorial.

Module will run

Occurrence Teaching cycle
A Spring Term 2019-20

Module aims

This module aims to present an understanding of the origins of diamagnetism, paramagnetism and ferromagnetism and the magnetisation process. This fundamental knowledge is then applied to the design of soft and hard magnetic materials, magnetic nanoparticles, magnetic thin films and multilayers; and their applications. The module extends into the development of the modern magnetic technologies of magnetic data storage, memory and spintronics.

Module learning outcomes

At the end of this module successful students will be able to:

Review the definitions and concepts of magnetism such as flux, flux density and field.

Understand and explain the fundamentals of magnetism and the magnetisation process:

  • The origins of diamagnetism, paramagnetism and ordered magnetism.
  • Concept of the demagnetising field and its role in magnetisation reversal processes.
  • Concept of magnetic anisotropy in terms of crystalline and shape effects and perpendicular anisotropy.
  • Formation of domains, domain walls and hysteresis in bulk materials.

Use these underpinning theories of magnetism to explain the magnetic behaviour and the applications of the following:

  • The origin and concept of single domain materials and reversal via the Stoner Wohlfarth mechanism.
  • Thin film magnetism and magnetic multilayers including methods of growth and techniques for measurement.
  • Hard and soft magnetic materials

Use the knowledge of magnetism and magnetic materials acquired to apply to key magnetic technologies:

  • Principles of magnetic recording in particular perpendicular media, Exchange Coupled Media, Heat Assisted Magnetic Recording, Microwave Assisted Magnetic Recording, Bit Patterned Media, the Read/Write Head.
  • Spintronics and applications: semi-classical free electron theory, classical magnetoresistance: Lorentz and anisotropic, spin-dependent transport: Giant Magnetoresistance, Tunneling Magnetoresistance, Magnetic Random Access Memories, Spin Transfer torque, Racetrack memory.

Module content

Syllabus

1. Origin and properties associated with diamagnetism and paramagnetism (both localised and of conduction electrons).

2. Ordered magnetism: ferromagnetism, antiferromagnetism and ferrimagnetism.  Curie-Weiss and Neel Laws, Weiss Molecular field, direct and indirect exchange interactions, band ferromagnetism.

3. The magnetisation process: hysteresis curves, domain theory, magnetostatic energy, demagnetising fields, magnetic anisotropy, domain walls.

4. Single Domain Particles, Stoner-Wohlfarth Model, applications of nanoparticles

5. Thin Film Magnetism and magnetic multilayers. Shape anisotropy, magnetostriction, perpendicular anisotropy, interlayer exchange coupling and exchange bias.

6. Thin film growth: epitaxial growth, Molecular Beam Epitaxy, Sputtering, Pulsed Laser Deposition, insitu characterisation: electron diffraction, Auger electron Spectroscopy and Quartz Crystal Monitors.

7. Magnetic Thin Film measurement: Vibrating Sample Magnetometer, Alternating Gradient Filed Magnetometer, X-Ray diffraction and reflection, neutron scattering, Magneto-Optic Kerr Effect, Magnetic Circular X-Ray Dichroism, Magnetic Force Microscopy, Lorentz Electron Microscopy.

8. Soft magnetic materials and their uses: design criteria and common materials e.g. SiFe, NiFe alloys, nanocrystalline and amorphous materials,

9. Hard magnetic materials and their uses: design criteria, BHmax and common materials: domain wall pinning, ferrites, AlNiCo, Rare-Earth transition metals.

10. Magnetic Data Storage: principles and challenges, perpendicular media, Exchange Coupled Media, Heat Assisted Magnetic Recording, Microwave Assisted Magnetic Recording, Bit Patterned Media, the Read/Write Head.

11. Spintronics and applications: semi-classical free electron theory, classical magnetoresistance: Lorentz and anisotropic; spin-dependent transport: Giant Magnetoresistance, Tunneling Magnetoresistance, Magnetic Random Access Memories, Spin Transfer torque, Racetrack memory.

Assessment

Task Length % of module mark
Essay/coursework
Magnetism Assignment
N/A 14
University - closed examination
Magnetism
1.5 hours 86

Special assessment rules

None

Reassessment

Task Length % of module mark
University - closed examination
Magnetism
1.5 hours 86

Module feedback

Exams - You will receive exam marks from eVision. Detailed model answers will be provided on the internet. You should discuss your performance with your supervisor.

Advice on academic progress - Individual meetings with supervisor will take place where you can discuss your academic progress in detail.

Assignments - Feedback on assignments will be returned within four weeks of the assignment deadline.

Indicative reading

Jiles D: Introduction to Magnetism and Magnetic Materials 2nd Ed (Chapman & Hall)

Blundell S: Magnetism in Condensed Matter (Oxford University Press)

Kittel C: Introduction to Solid State Physics (Wiley)



The information on this page is indicative of the module that is currently on offer. The University is constantly exploring ways to enhance and improve its degree programmes and therefore reserves the right to make variations to the content and method of delivery of modules, and to discontinue modules, if such action is reasonably considered to be necessary by the University. Where appropriate, the University will notify and consult with affected students in advance about any changes that are required in line with the University's policy on the Approval of Modifications to Existing Taught Programmes of Study.