Investigation of Domain Wall Dynamics in Transparent Ferromagnets Using High-Speed Photography

Abstract

The work is devoted to the investigation of the dynamics of domain walls and magnetic vortices arising within the domain walls of transparent ferromagnets. Initially, a review of methods for studying magnetization reversal dynamics is provided. Among the variety of these methods, high-speed photography based on the Faraday effect was selected for a more detailed consideration, since it allows for observing dynamic domain structures and determining the domain wall velocity with high accuracy. To optimize the use of the selected method, the study describes experimental investigations of magnetization reversal dynamics in materials with a high magneto-optical quality factor: Bi-containing ferrite—garnet films, GdFeCo, and yttrium orthoferrite. The choice of these materials is due to the fact that they exhibit high velocities of domain walls and magnetic vorteces arising in them, reaching up to 1.2 km/s in GdFeCo, approximately 10 km/s in garnet ferrites, and up to 20 km/s in yttrium orthoferrite. Additionally, ferrite garnets exhibit a periodic labyrinthine domain structure, enabling the use of magneto-optical diffraction to study the domain wall dynamics with high spatial resolution.