Self-induced drive of magnetic domains

Abstract

An electric current in a conductor can move a nearby magnetic domain even when all magnetic field gradients due to the current are canceled out; the motion comes from perturbations that are induced in the current by the domain field. A calculation is here made of the force that acts on a cylindrical bubble domain when a current flows in a thin adjacent sheet of a magnetoresistive material such as Permalloy. When the Permalloy layer is magnetized in its own plane, the direction of the force relative to the current depends on the direction of magnetization; the force can be rotated through 360° by rotating the magnetization through 180°. The greatest driving force possible is a few milligauss for each A/cm in the conducting layer.