This internship is part of the development of an experimental Kerr-effect magneto-optical imaging bench dedicated to the detailed study of magnetization mechanisms in soft ferromagnetic materials. The main objective is to design, instrument, and validate a device enabling the in-situ observation of Weiss magnetic domains and their evolution under controlled magnetic excitation.

The work will focus in particular on the analysis of Bloch magnetic walls, studying the mechanisms of 180° wall displacement, 90° wall displacement, as well as reversible wall swelling and magnetization rotation phenomena. Particular attention will be paid to the formation of closure domains and their role in nonlinear magnetization regimes up to magnetic saturation.

The materials studied will primarily be coarse-grained, non-oriented, soft ferromagnetic iron-silicon steels, representative of industrial soft materials used in the electrical power sector (electric motors, electrical transformers). The influence of granular texture, grain size, grain boundaries, magnetocrystalline anisotropy, and grain orientation on magnetization dynamics will be analyzed experimentally and interpreted using physical models.

From an instrumental perspective, the intern will participate in the implementation of an imaging system based on a polarized monochrome camera, coupled with polarized illumination, a linear polarizer, and a linear analyzer, all optimized for Kerr contrast detection. The work will also include the development of image acquisition and processing protocols.

physic, optics, magnetism