Effects of head field pulse shape and rise time on subnanosecond magnetization reversal in longitudinal thin film media

Micromagnetic simulations of planar isotropic magnetic thin film recording media are performed to study initial magnetization reversal processes in re sponse to pulses with linear and exponential ramps. Linear ramps lead to sm aller zero-crossing times T-0 than exponential ramps due to the more rapid field increase during the pulse ramps. It is shown that T-0 increases subst antially when the pulse amplitude is less than about half the anisotropy fi eld, in which case pulse overshoots are effective to reduce T-0. In additio n, the effects of exchange coupling and gyromagnetic damping are examined. (C) 2000 American Institute of Physics. [S0021-8979(00)83008-X].