Micromagnetic Study of Medium Noise Plateau

Medium noise characteristics and transition jitter in perpendicular magnetic recording are explored using micromagnetic simulation. A noise plateau for intermediate recording densities is observed for a recording layer of typical magnetization. The plateau is replaced by a normal linear dependence of noise on recording density for a low magnetization recording layer. We show analytically that a source of the plateau is similar to that producing the non-linear transition shift of signal. In particular, magnetostatic effects are predicted to produce positive correlation of jitter and thus negative correlation of noise at the densities associated with the plateau.