Abstract
A finite element read/write simulation was performed by solving the Poisson equation for a two-dimensional model of an antiferromagnetically coupled magnetic medium (AFC medium) and a thin-film-head system. The AFC medium is composed of two recording layers (top recording L1 layer, bottom recording L2 layer) and a thin intervening Ru layer. From a simulation of a di-bit pattern, we found that (1) when the coercive force Hc0 (L1) is smaller than Hc0 (L2), the L1 magnetization just recorded is rewritten by the applied reverse head field, and an extra-bit region appears in L1, (2) the extrabit is consolidated into a di-bit in L2 with increasing time, (3) the effect of the extrabit appears as a distortion in the output waveform, and (4) with increasing time, the output waveform changes so that its polarity becomes opposite to that at t = 0 sec. From the simulation at 423 kFRPI, it was found that (5) when Hc0 (L2) is small or large compared with Hc0 (L1), the thermal stability is improved at a finite small interlayer antiferromagnetic exchange coupling, and (6) for Hc0 (L1) ≈ Hc0 (L2), the thermal stability is improved with much larger interlayer antiferromagnetic exchange coupling.
