Influence of Notch Positions on Magnetization Reversal Processes in Permalloy Rings

Magnetoresistance measurements of permalloy rings with different arrangements of notches are performed to find out the conditions for repeatable and controllable magnetization reversal processes. It is observed experimentally that when the included angle between the notches and the field direction is 15°, the magnetization reversals are repeatable in the sweep-up and sweep-down processes, and the magnetization processes are controllable. In contrast, when the included angle between the notches and the field direction is 45° or 30°, the magnetization reversals are unrepeatable and random in the sweep-up and sweep-down processes. By appropriately arranging the positions of the notches, two-step and three-step transitions can be well controlled.