Section: New Results

The study of domain walls in micromagnetism

Participants: C. Courtès, R. Côte (IRMA)

A ferromagnetic material consists of a succession of isolated subdomains (known as the magnetic domains) in which the magnetic moments are aligned and point in the same direction. The interface separating two magnetic domains is called the domain wall and corresponds to a localized area where the direction of the magnetization suddenly changes. Mathematically, those domain walls correspond to the minimizers of the well-known micromagnatics energy. The magnetic behavior of ferromagnetic materials is due to the arrangement of the magnetic domains and to the dynamics of their domains walls. That dynamic is governed by the nonlinear Landau-Lifshitz-Gilbert equation. We study numerically and theoretically the stability and the interaction of two domain walls. Depending on the initial topological configuration, two domain walls may collide to give rise to a persistent profile or annihilate both, which results in aligning all magnetization vectors of the nanowire in the same direction.