Ferromagnetism at the nanoscale

Magnetic materials have long attracted a great deal of interest thanks to their multiple applications. Originally, ferromagnetic materials were used mainly in electrical engineering as a source of magnetic field or as a basic element in electrical machines and devices (transformers, motors, inductive components for electronics). However, the design of magnetic hard disks has revolutionized the world of data storage, directing research towards ever-smaller magnetic systems. The properties of magnetic materials are intimately linked to their size. The magnetic behavior of nanostructures can be significantly modified by the effects of interface phenomena and the combination of different materials.

This article focuses on the role of lateral confinement and interfaces with other materials on the properties of ferromagnetic systems. It also discusses their use in applications ranging from information technology to biotechnology. Nanostructuring has also revealed the mutual interaction between magnetization and conduction electron spin. This interaction is the basis of the so-called spintronic phenomena, which have made it possible to control magnetization by means other than a magnetic field. Various unconventional ways of manipulating magnetization are presented, based on the equation of motion of magnetization.

At the end of the article, readers will find a glossary and a table of the symbols used.