Micromagnetic calculation of erasure fields in perpendicular recording

The author has performed fully micromagnetic dynamic modeling of systems consisting of a perpendicular writer and a soft underlayer. The writer was approximately 9500 nm tall and 8000 nm wide, with two return poles each 1300 nm thick located 1600 nm from the yoke or top pole. The yoke thickness was 300 nm, and the top pole was 200 nm thick with a width of the pole tip of 160 nm. Dual three-turn coils were used to energize the writer with a current of 30 mA (0-to-peak). The writer was located 20 nm above a 120 nm thick soft underlayer. The entire system was modeled at a resolution of 20 nm everywhere with a time resolution of about 2.5 ps.