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Prof J J W A Robinson

Magnetism has been known and applied since ancient times, and it lies at the heart of modern technology, enabling the generation, control and transmission of electricity, data storage in computing, and countless other applications.

A detailed understanding of magnetism and its connection with electricity was a major achievement of 19th century physics; but the properties of lodestone, a magnetic material known since antiquity, were not understood until 1948, and predicting the magnetic properties of materials remains challenging today.

The development of practical magnetic materials is a notable success of modern materials science, achieving a 50 times increase in the performance of hard magnetic materials from the steels known in 1900 to the rare earth magnets now ubiquitous in compact devices. After briefly covering the nature and origins of magnetic behaviour, this short course will investigate how these properties can be controlled through material design and processing to meet the requirements of applications.

This lecture course will cover:

  • A brief recap of electromagnetism and the atomic origins of magnetism
  • The magnetic behaviour of materials: diamagnetism, paramagnetism, ferromagnetism, antiferromagnetism, ferrimagnetism, superparamagnetism
  • Properties and characteristics of ferromagnetic materials: hysteresis, domains, anisotropy, magnetostriction
  • Designing with magnetic materials: demagnetising effect, load lines and energy product
  • The properties and processing of practical magnetic materials: hard ferromagnetic materials (e.g. alnico, hard ferrites and Nd-Fe-B) and soft ferromagnetic materials (e.g. silicon steels, soft ferrites and Ni-Fe)
  • Selected applications of magnetic materials: motors, transformers, hard disk drives