Graded Media Design for Area Density of Up to 2.5 Tb/in $^{2}$

Feasibility of perpendicular magnetic recording up to an area density of 2.5 Tb/in² is investigated. Magnetic grains of 4 nm diameter with 1 nm oxide layer are required to achieve such a high density. Thermal stability of the grains is achieved by increasing the overall thickness of the grain. Magnetocrystalline anisotropy is graded within a grain in such a way that nucleation and propagation of the reversed domain wall matches with the available head field. Different design specifications are investigated to achieve higher objective function, i.e., energy barrier per switching field.