R&D: Adjacent Track Interference in 3D HAMR

Journal of the Magnetics Society of Japan has published an article written by T. Kobayashi,Graduate School of Engineering, Mie Univ., Japan, Y. Nakatani, Graduate School of Informatics and Engineering, Univ. of Electro-Communications, and Y. Fujiwara, Graduate School of Engineering, Mie Univ.

Abstract: “We examine the adjacent track interference (ATI) problem that arises during three-dimensional heat-assisted magnetic recording (3D HAMR) at 2Tbpsi per layer (total density of 4Tbpsi) where the medium consists of a high Curie temperature (HC) layer and a low Curie temperature (LC) layer. To evaluate the grain error distribution, the expected magnetization value is calculated using the grain error probability. Prior to considering the ATI in 3D HAMR, we examine the ATI problem for conventional HAMR. Since the temperature of the LC layer in the adjacent tracks while writing in the HC layer (HC writing) exceeds the LC Curie temperature, HC writing will erase the data of the LC layer in the adjacent tracks. Therefore, we investigate 3D HAMR combined with shingled magnetic recording. The ATI in an LC (upper, namely, surface) / HC (lower) layer structure is compared with that in an HC / LC layer structure. The latter is disadvantageous in relation to ATI caused by the small thermal gradient in the LC layer.“