Ring-shaped domain effective for the Bloch line memory

Abstract

A technique for stabilizing the ring-shaped stripe domain has been developed for improving the Bloch line memory. Selective grooving in the magnetic film provides for both formation and stabilization of the ring domain. The inside wall of the ring domain is used for ring domain stabilization, through its grooved edge affinity. The outside wall of the domain is stabilized away from the grooved edge by the natural domain width. The following features are found. (1) The ring-shaped domain is stable over a wide bias field range. (2) The demagnetizing field gradient, normal to the wall plane, can be kept almost the same at each position along the outside wall. (3) A stripe domain head can be formed controllably from a part of the ring-shaped domain, as required in the Bloch line memory for stripe-to-bubble domain conversion.