Finite Element Analysis of Alternating Write-Current-Induced Pole Tip Protrusion in Magnetic Recording Heads

This paper presents a finite element analysis of alternating write-current-induced pole tip protrusion (WPTP) generated in longitudinal magnetic recording (LMR) heads. An integrated magneto-thermal-mechanical model is developed for the simulations of the electromagnetic Joule heating generated in the LMR writer, the slider temperature distribution, and the slider deformation during writing. The computed results are compared with the experimental measurements in terms of writer resistance and inductance, the WPTP, and temperature rise at reader location. It is found that eddy currents are strongly induced near the surfaces of write poles, while the eddy currents induced in write coils are negligibly weak. The results show that the eddy current loss in the write poles dominates over the Joule heat generated in the write coils. It is also found that the maximum protrusion appears near the write pole in the overcoat and the protrusion profile is sharper than that induced by equivalent direct write current and coil resistance