Title :
Writeability Enhancement in Perpendicular Magnetic Multilayered Oxide Media for High Areal Density Recording
Author :
Choe, Gunn ; Park, Jihoon ; Ikeda, Yoshihiro ; Lengsfield, Byron ; Olson, Terry ; Zhang, Kezhao ; Florez, Sylvia ; Ghaderi, Arien
Author_Institution :
Media Dev., Hitachi Global Storage Technol., San Jose, CA, USA
Abstract :
A systematic investigation of the switching behavior and writeability characteristics of perpendicular magnetic oxide media was performed by varying the number of oxide layers as well as the anisotropy Ku gradient in multilayered oxides. The media switching behavior highly depends on the magnetic volume of laterally exchange-coupled cap layer as well as the vertical exchange coupling between oxide and cap layers. The media switching field is significantly reduced with incoherent switching mode. The media writeability is further enhanced by employing the multilayered oxides whose anisotropy values vary. Higher Ku graded oxide media exhibits improved resolution, sharper transition, and higher signal-to-noise ratio. An analytical 9-spin model is used to study the impact of anisotropy grading, intergranular and interlayer exchange coupling on writeability and noise performance. The 9-spin model is found to qualitatively agree with the experimental results. Both model and experiment indicate that optimal tuning of the media anisotropy and exchange to the head design is critical in attaining good recording performance.
Keywords :
exchange interactions (electron); magnetic multilayers; magnetic switching; perpendicular magnetic anisotropy; perpendicular magnetic recording; anisotropy grading; cap layers; head design; high areal density recording; intergranular exchange coupling; interlayer exchange coupling; magnetic volume; optimal tuning; perpendicular magnetic multilayered oxide media; signal-to-noise ratio; spin model; switching behavior; vertical exchange coupling; writeability enhancement; Anisotropic magnetoresistance; Couplings; Magnetic recording; Media; Perpendicular magnetic anisotropy; Switches; Anisotropy grading; multilayered oxides; perpendicular magnetic recording; switching mode;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2010.2074190