28th USIAS Fellows seminar: How Magnetism Changed the World Three Times

2000 years of magnetic devices a) Chinese South-pointer 1st century AD and b) Hard-disc drive 21st century.

By Michael Coey, USIAS Fellow 2014

Magnetism has been a microcosm of the history of science for more than two millennia. The weirdness of magnetic repulsion and attraction, its directionality, and the opportunity a magnet affords to manipulate a force field have catalyzed an understanding of the natural world that launched three revolutions.

First was harnessing the directional nature of the magnetic force in the compass that led to the exploration of the planet in the 15^th century. Second was discovery of the relation between electricity and magnetism that sparked the electromagnetic revolution of the 19^th century and irrevocably transformed the conditions of human life and communication. Third is the big data revolution that is currently redefining human experience while radically redistributing knowledge and power.

The emergence of magnetic science demanded imagination and acute observational ability, which led to the theory of classical electrodynamics, and then associated the magnetic field with specific materials through the angular momentum of elementary charged particles, as well as with electric currents and the Earth itself. Our fundamental understanding of the magnetism of electrons in solids is rooted in quantum mechanics and relativity. Yet only since the latter part of the 20^th century has fundamental theory succeeded in underpinning the rational design of new functional magnetic materials and the creation of spin electronic devices that can be reproduced on ever-smaller scales, leading to the disruptive, 60-year exponential improvement in electronic information storage.

This talk will give an overview of the evolution of ideas in one of the oldest continuously-studied areas of natural science, and also provide a thumbnail sketch of the USIAS project "Microfluidics without walls" carried out in cooperation with Bernard Doudin (IPCMS) and Thomas Hermans (ISIS).