Micromagnetic analysis of the effect of intergranular exchange on thermal stability in magnetic recording (III): Perpendicular media

We describe micromagnetic simulations to examine the effect of intergranular exchange on thermal stability of dibit transitions in perpendicular media. We found that, without an intergranular exchange, pure magnetostatic interactions induce substantial magnetization decay; a weak exchange, however, reduces the decay significantly. In addition, the reduction is more pronounced at reduced magnetostatic interactions. To achieve a high signal-to-noise ratio (SNR) and simultaneously to reduce thermal decay, a medium with reduced magnetostatic interactions is required and a weak exchange should be included. Reducing the spacing between the soft underlayer and the recording medium enhances thermal stability. The effect is more pronounced at higher linear densities.