Hysteresis magnetoresistance and micromagnetic modeling of Ni microbelts

Magnetization reversal process in a single nickel microbelt is investigated by measuring magnetoresistance (MR). A hysteresis MR curve is observed, which consists of a reversible bell-shaped curve under high magnetic field and an irreversible discontinuity under low magnetic field. A micromagnetic simulation is performed for understanding the underlying physics behind the MR curve. The hysteresis is ascribed to the competition of exchange energy and Zeeman energy, and the irreversible discontinuity is attributed to the formation of domain walls and vortices.