Thermal Stability of Granular-Type FePt-MgO Perpendicular Recording Media With Soft Underlayers

摘要

Thermal stability of written bits on [MgO xnm/FePt ynm]{sub}3/MgO4-nm/SiO{sub}2 4-nm/Fe-Ta-C 200-nm/Glass perpendicular media with two different structure having different stability factor has been investigated by magnetic force microscopy (MFM) equipped with in-situ sample heating system up to 200 ℃. The disk with x = 2 nm, and y = 2.5 nm, shows no observable degradation even at 200 ℃, indicating high thermal stability of this disk. On the other hand, for the disk with x = 4 nm, and y = 3 nm, some reversed domains are observed in the center area of 10 kfci bits at 200 ℃ and some minor changes are found in the transition area of the higher frequency bits. The decay at a higher temperature is interpreted in terms of estimated thermal stability factor from MFM signal decay.