Effect of damping constant on the switching limit of a thin-film recording head

This article presents a micromagnetic study on the dynamics of magnetic flux transfer in the pole tip region of a stitched-pole magnetoresistance/thin-film head. Three-dimensional vortices are found inside the pole tips. The flux at the ABS surface is conducted by the motion of the vortex moving in the cross-track direction. The resulting head field well follows the driving flux with little phase delay and little dependence on the damping constant, alpha. The vortex motion under the driving flux maintains similar speed even when the damping constant is decreased to zero. In this case, it is found that in addition to the motion of the vortex, spins precess locally with small cone angles, resulting in small head field fluctuations. It is concluded that the speed of magnetization flux reversal in the pole tip region is not limited by small damping constant. (C) 1999 American Institute of Physics. [S0021-8979(99)72208-5].