Title :
High-density perpendicular magnetic recording media of granular-type (FePt/MgO)/soft underlayer
Author :
Suzuki, Takao ; Zhang, Zhengang ; Singh, Amarendra K. ; Yin, Jinhua ; Perumal, Alagarsamy ; Osawa, Hiroshi
Author_Institution :
Inf. Storage Mater. Lab., Toyota Technol. Inst., Nagoya, Japan
Abstract :
Perpendicular magnetic recording media, composed of granular-type FePt-MgO films on Fe-Ta-C soft magnetic underlayer (SUL), have been fabricated on to 2.5-in glass disks. [001] textured FePt granular films with high-perpendicular magnetic anisotropy were obtained by annealing the FePt/MgO multilayer films. The FePt grain size, perpendicular coercivity, magnetic activation volume, and the exchange coupling between the FePt grains were found to be strongly dependent on the initial multilayer structures and the annealing conditions. The recording performance of the disks was evaluated by a spin-stand. The obtained results reveal a close correlation between the recording performance and magnetic properties. The thermal stability of the granular-type FePt media was studied using high-temperature magnetic force microscopy (MFM) technique, equipped with in situ sample heating, in the temperature range 25°C-200°C. The estimated signal decay at high temperature is ascribed to the temperature dependent magnetic anisotropy behavior.
Keywords :
exchange interactions (electron); ferromagnetic materials; iron alloys; iron compounds; magnesium compounds; magnetic annealing; magnetic force microscopy; magnetic multilayers; magnetic thin films; perpendicular magnetic anisotropy; perpendicular magnetic recording; soft magnetic materials; tantalum alloys; thermal stability; 25 to 200 C; Fe-Ta-C soft magnetic under-layer; FePt-MgO; FePt-MgO multilayer films; FeTaC; annealing conditions; estimated signal decay; exchange coupling; grain size; granular-type FePt MgO soft underlayer; granular-type FePt-MgO films; high-density perpendicular magnetic recording media; high-perpendicular magnetic anisotropy; high-temperature magnetic force microscopy technique; in situ sample heating; magnetic activation volume; multilayer structures; perpendicular coercivity; spin-stand; temperature dependent magnetic anisotropy behavior; textured FePt granular films; thermal stability; Annealing; Disk recording; Magnetic anisotropy; Magnetic films; Magnetic force microscopy; Magnetic multilayers; Perpendicular magnetic anisotropy; Perpendicular magnetic recording; Soft magnetic materials; Temperature dependence; FePt; granular-type structure; magnetic anisotropy; perpendicular magnetic recording media; spin stand;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2004.838073