Optimization of perpendicular recording with shielded pole head

Recently there is an arising interest in perpendicular recording due to its intrinsic advantages for ultra-high recording density. At present, one key issue for increasing the recording density is how to minimize the system noise, which is dominated by the media transition noise and directly related to the switching field distribution (SFD) of the magnetic media. SFD is the dispersion of the lowest magnetic field required to switch the magnetization directions of grains. In granular perpendicular media, the magnetocrystalline anisotropy easy axes of the grains in the medium are virtually in the direction normal to the film plane. In recent head design, a shielded pole head/SUL, which is the combination of a trailing shield with a MP head, is proposed to provide high field gradient in recording. However, the trailing shield also introduces a, large horizontal field component on the media plane and consequently provides a larger switching field angle compared with the MP head. By optimizing the SP/SUL geometry we can obtain the desired switching field angle on the media plane. A 2-D micromagnetic model, which :is based upon the Landau-Lifshits-Gilbert equation, was used to simulate the dynamic recording process and evaluate the designed recording system.