Effect of pole tip anisotropy on the recording performance of a high density perpendicular head

A perpendicular recording head for an areal density of 1 Tbit per square inches has been developed using a self-consistent three-dimensional (3D) micromagnetic model. The soft underlayer and the recording layer have been included in the model. The head consists of a probe type tip protruding from a collar. The tip has saturation magnetization (M-s) of 24 kG while the collar has lower M-s of 10 kG. The magnitude and orientation of anisotropy field (H-k) in the tip is varied to obtain the best recording performance. A perpendicularly oriented H-k in the tip reduces flux spreading, thereby enhancing the recording field in the writing track while reducing the offtrack field. However, simulations show that the head's performance suffers in terms of high remanent field and slower frequency response. Simulations show that a lower remanent field can be achieved by applying ac demag pulse to the tip. A detailed comparison has been made between two cases of perpendicular H-k of 1 kOe and longitudinal H-k of 10 Oe in the tip of the head. Results show a clear tradeoff in terms of recording field and frequency response. Finally, simulations show that the designed head is capable of recording areal density of 1 TBPSI on a recording layer of M-s of 700 emu/cc, thickness of 20 nm, H-k of 18 kOe and average grain diameter of 6 nm. (C) 2003 American Institute of Physics.