Study on magnetization reversal of perpendicular recording media by in-field MFM observation

In-field MFM observation technology was employed to study the perpendicular recording medium under various perpendicular magnetic fields. A magnetization reversal field (HR) map method was performed to reveal the magnetization reversal behavior of the medium. Under low magnetic field, some specific areas firstly reversed at a random position and then these reversed areas grew up. Under a high magnetic field, the magnetization reversal process tended to occur at the boundary between the reversed area and the non-reversed area. The simulation results implied that the long-range spatial interaction exists in the real media, which results in the bigger magnetic cluster. A simple experimental method was first proposed to estimate activation volume. The experimental activation volume agreed with the result calculated by the dynamic coercivity method.