Study of magnetization reversal of Co/Pd bit-patterned media by micro-magnetic simulation

Abstract

Bit-patterned media based on a single-bit-per-island may be a promising candidate for perpendicular magnetic recording at the Tb/in2 level because they could provide a lower noise and higher density. The understanding of magnetization reversal processes in such patterned media is important. In this work, the range of single domain island size based on Co/Pd bit-patterned media was determined. Demagnetization effect, dipolar interactions and switching field distribution (SFD) for bit-patterned media were quantitatively studied by the simulation based on Landau-Lifshitz-Gilbert equation. The total hysteresis loops and SFD were comparable with the experiment ones. The SFD increased from 2σ=1.2kOe (as the calculated intrinsic SFD) to the experimental value of 1.9kOe due to dipolar interactions which is in a good agreement with the experimental results (2.0kOe). Optimized patterned structure with a minimized SFD and maximized data storage densities was found to have an island size of 10nm and islands separation of 20nm. The calculated ratio of SFD/Hc (Hc: the coercivity) is 9.2%, which is below the threshold of 10% for 1Tb/in2 pattern media.