Wall Streaming: A Gyromagnetically Induced Kind of Wall Motion

A field applied perpendicular to a Bloch wall does not favor one of the adjacent domains. Nevertheless, the gyromagnetic behavior of the wall magnetization, i.e., the precession around the field instead of a rotation towards the field direction, may induce a wall displacement. This has been observed experimentally in Permalloy films with a thickness larger than 0.1 μ when a pulse field has been applied along the hard axis with a pulse risetime smaller than 20 nsec. The effect (called wall streaming) is compared, from a theoretical point of view, with the wall behavior in a pulse field applied parallel to the wall.