Effect of applied fields on media noise in longitudinal thin film media: Simulation studies

During the writing of transitions in longitudinal magnetic recording media, the fields from the record head can perturb previous transitions in the media. This perturbation of the previous transition may cause an increase of the noise of the transition affecting the probability of correctly reading the data.; This effect is likely to be small and hard to observe experimentally, so a computer simulation of the magnetic recording process was used for the work in this dissertation. The model is used to investigate the sources of readback pulse shift of isolated transitions overwritten with dc fields. The pulse shift is found to be a result of both changes in the shape of the transition due to the applied field, and the response of the readback head to the magnetic charges present in the media. A novel analytical model that can quantify the shape change of the transition is proposed. The model is validated against both experimental and simulation results.; The noise enhancement of a transition during the writing of another transition is investigated using the computer simulation. The results show that the writing field can have some effect on the noise of a previous transition. The noise enhancement is a function of the length of the magnetic transition in the media, the distance to the transition being written, and the write field gradient. With the write field gradient held constant, a higher coercivity media shows more noise enhancement. This is due to the smaller transition length in the higher coercivity media, allowing the next transition to be written closer, resulting in a higher field perturbing the transition.