Computer simulation of magnetization switching behavior in high-data-rate hard-disk media

We have investigated magnetization switching behavior in high-data-rate hard-disk media by micro-magnetic simulation. We found that the remanence coercivity measured by a short-pulse-field depended on the field-pulse shape. The time integration of external field over the remanent coercivity for a long-pulse-field, namely switching force integration (SFI), was an essential factor for the switching. We also found that the optimum writing field, H_w must be increased by only 0.4 kA/m per MB/s independent of the linear recording density. Overwrite (OW) value decreased by 1 dB per percentage point of H_w and did not depend on the data-transfer rate. The recording characteristics at high data transfer rates were not degraded if only a writing field of H_w was applied to the film. The simulation results were consistent with the results of read/write experiments especially OW characteristics up to 80 MB/s.