Dynamic Field Gradient and Erasure After Write for High Data Rate Recording

Extensive micromagnetic simulations are performed to investigate the impact of the current overshoot amplitude (OSA) on the writer dynamics. The field risetime, dynamic gradient, bubble width, as well as erasure risk due to large stray fields in the neighbouring tracks during the switching are all shown to be very sensitive to the OSA. Numerical results show that increasing OSA can sharply improve the field risetime. However, it also leads to a larger write bubble expansion during switching which could result in a wider track width and reduce track per inch (TPI) capability. The risk of side track erasure for different overshoot conditions are evaluated and also tend to increase with higher OSA. Futhermore, results for remnant fields in the media produced by the writer are shown to be extremely sensitive to the choice of damping parameter used in the simulations.