Requirements for soft magnetic underlayer (SUL)-Micromagnetic simulations of single-pole-type write heads and SUL systems

► Write heads were simulated using micromagnetics. ► A SUL Bs of 10-12 kG and t-SUL of 30-45 nm would be sufficient. ►Antiferromagnetic coupling in the SUL affected the head and SUL magnetization. ► Magnetization under the coil responded first in the head to the current. ► Response at the main pole tip was quite slow.