Relationship between Overwrite Characteristics and Linear Velocity in Mark Edge Recording with Phase-Change Media

In this paper, we describe the relationship between overwrite characteristics and linear velocity in mark edge recording with phase-change media. Overwrite jitter is reduced for a disk in which the absorptivity of the crystalline state (A c) has been designed to be higher than that of the amorphous state (A a). When linear velocity is lower than 6 m/s, however, overwrite jitter is suppressed even in disks with A a higher than A c. This jitter suppression at low linear velocity cannot be explained simply in terms of thermal diffusion or critical cooling rate. This paper presents a “preceding crystallization” model for a jitter-suppression mechanism in which a previously recorded amorphous mark crystallizes before the scanning laser spot reaches it. Computer simulation confirms the feasibility of this mechanism at linear velocities lower than 6 m/s.