Mechanism of 90° wall motion in thin film heads

The interaction between the rotational motion of magnetization and wall movement are investigated for an infinite strip of magnetic film with closure domains. When an external field is applied, the direction of magnetization is assumed to curl parabollicaly near the 90° walls. The 90° wall will move to decrease the energy associated with this curling. This movement can be described by the equation of rotational motion for the wall. The switching time relating to a 90° wall is fairly short (6 - 18 nsec) calculated by solving the equation of motion. It is due to the acceleration of the wall movement by the magnetization rotation.