High Recording Performance of Bit-Patterned Media With Two-Layer Inclined Anisotropy ECC Dots

• Published in: IEEE transactions on magnetics 2017-02, Vol.53 (2), p.1-7
• Main Authors: Honda, N., Yamakawa, K.
• Format: Article
• Language: English
• Subjects: Analytical models; Anisotropic magnetoresistance; Anisotropy; Applied field angle dependence; bit-patterned media; Couplings; Cubes; Dependence; Granular materials; Granular media; Head; Inclination angle; inclined anisotropy; Magnetic heads; Magnetism; Media; Recording; recording simulation; Simulation; Switches; Switching; switching field; two-layer exchange coupled composite
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2016.2616415

A simplified exchange coupled composite (ECC) dot structure with a reduced switching field and small applied field angle dependence in the switching field is proposed. It was found from a spin model analysis that a reduced switching field as well as a small applied field angle dependence of the field is obtainable even for two-layer ECC dot when the anisotropy axis is weakly inclined with an increased anisotropy for the soft layer. The switching properties of the two-layer ECC dots were confirmed using a micromagnetic simulation. A minimum normalized switching field of 0.51 was obtained for a two-layer ECC dot model of stacked cubes with a size of 5 nm and an anisotropy inclination angle of 10°. Recording simulation on a bit-pattered medium of the two-layer ECC dot array suggested the possibility of a high areal density recording beyond 4 Tdot/in 2 by shingled recording. It was also confirmed by simulation that the proposed inclined anisotropy ECC dot could be applicable to granular media for narrow track recoding.