Design consideration of ultrahigh-density perpendicular magnetic recording media

Design consideration of double-layered perpendicular magnetic recording media for ultrahigh-density recording was studied based on a micromagnetic model. It was found that the introduction of an appropriate exchange coupling between grains remarkably improves the recording resolution of the media. The essential role of the exchange coupling could be understood that it increases the perpendicular M-H loop slope, which has the same contribution to the resolution as the head field gradient. Large values for the product of the M-H loop slope parameter and the head field gradient are expected to result in small transition widths less than 10 nm. Consideration of thermal stability of the media including effects of the demagnetizing field and the M-H loop slope suggested that Co-Cr based media would meet the magnetic properties for recording of 200 Gb/in² but may not for higher densities. Media with higher anisotropy fields like Fe-Pt would be the candidate