Micromagnetic model of perpendicular head and double-layer media for 100 Gb/in/sup 2/

A system including a perpendicular recording head, a soft underlayer, and a recording layer has been studied using a micromagnetic simulation. The model uses Voronoi cells to represent the recording layer and cubic cells for the soft underlayer and head. The total field consists of the magnetostatic interaction field, the demagnetization field, the exchange field, the anisotropy field, and the field generated by the nontip region of the head. The geometrical configuration of the pole tips and soft underlayer was optimized for. performance at 100 Gb/in/sup 2/. It is demonstrated that high anisotropy fields in the soft underlayer have only small effects on peak fields and gradients. This suggests that low permeability underlayers are an effective way of combating stray field effects. Simulations of the recording layer show the effects of increasing anisotropy on reducing trackwidth. We find a large increase in the perpendicular recording field caused by the permeability of the recording layer exceeding that of free space. This should greatly aid the achievement of adequate recording fields at high density.