A study of head field gradient and velocity on transition noise

A model of the micromagnetic fluctuation in the writing process is proposed. Both higher linear velocity and high field gradient increase the transition noise in the unsaturated region which is related to a lower transition noise in the saturated region as required. The model is as follows: when writing in a slowly turning off (or decreasing) write field, i.e., low field gradient or low linear velocity, the recording magnetization in the transition is reconstructed to a more relaxed state. On the other hand, magnetization at the transition is not relaxed by rapidly turning off the write field, i.e., high field gradient or high linear velocity