Micromagnetic studies of thermal stability of media signal and noise

Summary form only given. As the magnetic recording densities are beyond 20Gbit/in
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, the grain size of the thin film recording media has been significantly reduced in order to reduce the transition noise at high recording densities. The current stale of the art media for MR application have grain size around 100 Å to 200 Å. Thermal stability of these interacting grains becomes one of the critical concerns in media development. Particular important is the understanding the signal and noise behaviors of these media when subject to thermal decay. In this study, a Monte Carlo method is incorporated into a full micromagnetic model. The Landau-Lifshilz equation of motion is ulilired to obiain the dynamics during the thermal assisted switching in the thin film media. The model uses a new algorithm to calculate the thermal agitation, which can bcttcr simulate the collective switching behavior. Dibit transitions are simulated by mimicking the actual recording process in a hard disk drive. The recording head field is calculated using aSzczech head with a write gap of 0.3 μm and is flying 30nm above thc surfacc of the recording media. The maximum head field at the center of the recording media is set to be twice the media coercivity. During and atler the transitions are rccordcd, media is subject to thermal decay and thus, magnetization profiles versus time have been recorded. Playback voltage was calculated using the reciprocity principle for a MR head. Noise power was calculated. The total noise power includes the DC noise and transition noise.