Visualization of magnetization processes of soft magnetic composites by the magneto-optical imaging technique

Attractive features of soft magnetic composites (SMCs) are high resistivity, isotropic three-dimensional flux behavior, and easy compression into the complicated shapes required in electromagnetic devices. Comprehensive understanding of the materials will help optimize design of electromagnetic devices. This paper presents the magnetization processes in a SMC sample in micron scale by means of the magneto-optical imaging technique. The sample was magnetized by magnetic fields tangential or perpendicular to the observation surface. It is observed that the flux density is higher at the particle region but lower at the interparticle space. When a tangential field is applied, the stray fields change polarization at the particle boundaries. Both results suggest that the magnetized sample behaves as a collection of individual magnetized particles rather than as a uniform and continuous magnetic substance such as soft iron although there are some interactions between neighboring particles. 2007 American Institute of Physics