Quasi-lifetime topography of magnetic domain movements in grain oriented (100) [001] Fe−3 wt% Si Polycrystals Using White Synchrotron Radiation. The influence of an external magnetic field

Abstract

The magnetization state within (100) [001] Fe−3wt% Si polycrystals of intermediate thickness (μoto ≈ 1.0) is controlled by the axial field of a magnetizing coil directed along either an easy [010]‐ or hard [011]‐magnetization axis. Typical topograph exposure times are between 24 and 120 s for chosen magnetization states throughout (dc induction) hysteresis cycles. When the magnetic field is applied along the easy [010]‐magnetization axis, [001]‐stripe domains, initially present at zero field, show extended growth into areas previously occupied by [010]‐stripe domains. In this experiment most of the stripe domains are completely replaced by 90° (chevron) closure domains after rapid reverse switching from positive to negative saturation states. In an alternative experiment the magnetic field is applied along a hard [011]‐magnetization axis of a similar crystal. Fields of 100 A/m immediately produce [010]‐stripe domains whose straight fronts advance along an easy [010]‐magnetization axis with further field increases. High saturation state reverse switching produces maximum or minimum stripe domain coverage which is dependent on the final field direction. Hysteresis (pinning) effects are detected at single defect positions, where pronounced Bloch wall bowing occurs during the crystal magnetization.