Micromagnetic analysis of the effect of intergranular exchange on thermal stability in magnetic recording. II. Slightly oriented longitudinal media

For pt.I see ibid., vol.38, no.2, p.1405-16 (Mar. 2002). We describe micromagnetic simulations to examine the effect of intergranular exchange on thermal stability of dibit transitions in slightly oriented longitudinal media. We found that, by increasing the intergranular exchange and the anisotropy orientation ratio, Ku
is reduced to maintain the fixed M/sub r/t, the writing coercivity, and the average grain planar area. Within the drive working temperatures (T/spl les/350 K), to increase signal-to-noise ratio (SNR) at 10/sup 9/ s, both the intergranular exchange and the anisotropy orientation ratio must be reduced. However, if both K/sub u/ and M/sub r/t are fixed, for a constant circumferential loop closure field, a larger SNR is always exhibited at a higher OR(M/sub r/) initially and at 10/sup 9/ s. For both cases, if the intergranular exchange cannot be neglected, SNR always slightly increases with increasing OR(M/sub r/).