R&D: Influence of Design Parameters on Adjacent Track Interference in Heated-Dot Magnetic Recording

Journal of the Magnetics Society of Japan has published an article written by T. Kobayashi, Graduate School of Engineering, Mie Univ., Japan, and I. Tagawa, Electrical and Electronic Engineering, Tohoku Institute of Technology, Japan.

Abstract: “We discuss the influence of design parameters on adjacent track interference (ATI) in 4 Tbpsi heated-dot magnetic recording where the parameters are the mean Curie temperature, Curie temperature variation, anisotropy constant ratio, dot size variation, Gilbert damping constant, writing field magnitude, and writing field angle. We calculate the dot height to achieve a bit error rate of 10^-3 after adjacent track writing as a function of the design parameters. The dot height must be increased when we choose a lower mean Curie temperature, since the thermal gradient decreases simultaneously. The adjacent track temperature is related to the Curie temperature variation via the writing temperature. ATI is strongly affected by the anisotropy constant ratio. The dot height must be increased as the dot size variation increases, since the probability of a small dot appearing increases. The Gilbert damping constant has an effect on ATI. Since a writing field magnitude of 10 kOe is relatively small against the anisotropy field, the increase in the dot height is relatively small when the writing field magnitude increases from 10 to 15 kOe or the writing field angle changes from 180 to 135 deg.“